Merge pull request #7993 from dcw803/master

imported my solutions to this week's tasks (both in Perl, first in C)

15 files changed, 905 insertions, 44 deletions

diff --git a/challenge-213/duncan-c-white/README b/challenge-213/duncan-c-white/README
index bf3941e44d..036a8e0734 100644
--- a/challenge-213/duncan-c-white/README
+++ b/challenge-213/duncan-c-white/README
@@ -21,7 +21,7 @@ Example 3
 MY NOTES: sounds very easy.  Select evens; sort them; select odds; sort them,
 then append sorted lists together.
 
-GUEST LANGUAGE: As a bonus, I've had a go at translating ch-2.pl into C,
+GUEST LANGUAGE: As a bonus, I've had a go at translating ch-1.pl into C,
 look in the C/ directory for that.
 
 
@@ -67,5 +67,5 @@ MY NOTES: hmmm.. weird "list of routes" data format.  Easier if we can
 convert the data into "normal" node -> list possible next nodes form.
 Shortest route means: find all routes and min() them?
 
-GUEST LANGUAGE: I will translate ch-2.pl into C tomorrow. Run out of time
-to do it today.
+GUEST LANGUAGE: As a bonus, I've had a go at translating ch-2.pl into C,
+look in the C/ directory for that.
diff --git a/challenge-214/duncan-c-white/C/Makefile b/challenge-214/duncan-c-white/C/Makefile
new file mode 100644
index 0000000000..3a6ebb224c
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/Makefile
@@ -0,0 +1,17 @@
+# Makefile rules generated by CB
+CC	= gcc
+CFLAGS	= -Wall -g
+BUILD	= ch-1
+
+all:	$(BUILD)
+
+clean:
+	/bin/rm -f $(BUILD) *.o core a.out
+
+args.o:	args.c
+ch-1:	ch-1.o args.o parseints.o printarray.o rank.o
+ch-1.o:	ch-1.c args.h parseints.h printarray.h rank.h
+parseints.o:	parseints.c args.h parseints.h printarray.h
+printarray.o:	printarray.c
+rank.o:	rank.c rank.h
+
diff --git a/challenge-214/duncan-c-white/C/README b/challenge-214/duncan-c-white/C/README
new file mode 100644
index 0000000000..ba67141dfe
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/README
@@ -0,0 +1,10 @@
+Thought I'd also have a go at translating ch-1.pl and ch-2.pl (coming soon) into C..
+
+Both C versions produce very similar (non-debugging and debugging)
+output to the Perl originals.
+
+These C versions use some of my regular support modules:
+- my command-line argument processing module args.[ch],
+- my csvlist-of-int parsing module parseints.[ch], and
+- my int-array printing module printarray.[ch].
+- a NEW clone of printarray.[ch] that prints RANKS: rank.[ch]
diff --git a/challenge-214/duncan-c-white/C/args.c b/challenge-214/duncan-c-white/C/args.c
new file mode 100644
index 0000000000..20c21e6c30
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/args.c
@@ -0,0 +1,234 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+
+bool debug = false;
+
+
+// process_flag_noarg( name, argc, argv );
+//	Process the -d flag, and check that there are no
+//	remaining arguments.
+void process_flag_noarg( char *name, int argc, char **argv )
+{
+	int arg=1;
+	if( argc>1 && strcmp( argv[arg], "-d" ) == 0 )
+	{
+		debug = true;
+		arg++;
+	}
+
+	int left = argc-arg;
+	if( left != 0 )
+	{
+		fprintf( stderr, "Usage: %s [-d]\n", name );
+		exit(1);
+	}
+}
+
+
+// int argno = process_flag_n_args( name, argc, argv, n, argmsg );
+//	Process the -d flag, and check that there are exactly
+//	n remaining arguments, return the index position of the first
+//	argument.  If not, generate a fatal Usage error using the argmsg.
+//	
+int process_flag_n_args( char *name, int argc, char **argv, int n, char *argmsg )
+{
+	int arg=1;
+	if( argc>1 && strcmp( argv[arg], "-d" ) == 0 )
+	{
+		debug = true;
+		arg++;
+	}
+
+	int left = argc-arg;
+	if( left != n )
+	{
+		fprintf( stderr, "Usage: %s [-d] %s\n       Exactly %d "
+			"arguments needed\n", name, argmsg, n );
+		exit(1);
+	}
+	return arg;
+}
+
+
+// int argno = process_flag_n_m_args( name, argc, argv, min, max, argmsg );
+//	Process the -d flag, and check that there are between
+//	min and max remaining arguments, return the index position of the first
+//	argument.  If not, generate a fatal Usage error using the argmsg.
+//	
+int process_flag_n_m_args( char *name, int argc, char **argv, int min, int max, char *argmsg )
+{
+	int arg=1;
+	if( argc>1 && strcmp( argv[arg], "-d" ) == 0 )
+	{
+		debug = true;
+		arg++;
+	}
+
+	int left = argc-arg;
+	if( left < min || left > max )
+	{
+		fprintf( stderr, "Usage: %s [-d] %s\n       Between %d and %d "
+			"arguments needed\n", name, argmsg, min, max );
+		exit(1);
+	}
+	return arg;
+}
+
+
+// process_onenumarg_default( name, argc, argv, defvalue, &n );
+//	Process the -d flag, and check that there is a single
+//	remaining numeric argument (or no arguments, in which case
+//	we use the defvalue), putting it into n
+void process_onenumarg_default( char *name, int argc, char **argv, int defvalue, int *n )
+{
+	char argmsg[100];
+	sprintf( argmsg, "[int default %d]", defvalue );
+	int arg = process_flag_n_m_args( name, argc, argv, 0, 1, argmsg );
+
+	*n = arg == argc ? defvalue : atoi( argv[arg] );
+}
+
+
+// process_onenumarg( name, argc, argv, &n );
+//	Process the -d flag, and check that there is a single
+//	remaining numeric argument, putting it into n
+void process_onenumarg( char *name, int argc, char **argv, int *n )
+{
+	int arg = process_flag_n_args( name, argc, argv, 1, "int" );
+
+	// argument is in argv[arg]
+	*n = atoi( argv[arg] );
+}
+
+
+// process_twonumargs( name, argc, argv, &m, &n );
+//	Process the -d flag, and check that there are 2
+//	remaining numeric arguments, putting them into m and n
+void process_twonumargs( char *name, int argc, char **argv, int *m, int *n )
+{
+	int arg = process_flag_n_args( name, argc, argv, 2, "int" );
+
+	// arguments are in argv[arg] and argv[arg+1]
+	*m = atoi( argv[arg++] );
+	*n = atoi( argv[arg] );
+}
+
+
+// process_twostrargs() IS DEPRECATED: use process_flag_n_m_args() instead
+
+
+// int arr[100];
+// int nel = process_listnumargs( name, argc, argv, arr, 100 );
+//	Process the -d flag, and check that there are >= 2
+//	remaining numeric arguments, putting them into arr[0..nel-1]
+//	and returning nel.
+int process_listnumargs( char *name, int argc, char **argv, int *arr, int maxel )
+{
+	int arg=1;
+	if( argc>1 && strcmp( argv[arg], "-d" ) == 0 )
+	{
+		debug = true;
+		arg++;
+	}
+
+	int left = argc-arg;
+	if( left < 2 )
+	{
+		fprintf( stderr, "Usage: %s [-d] list_of_numeric_args\n", name );
+		exit(1);
+	}
+	if( left > maxel )
+	{
+		fprintf( stderr, "%s: more than %d args\n", name, maxel );
+		exit(1);
+	}
+
+	// elements are in argv[arg], argv[arg+1]...
+
+	if( debug )
+	{
+		printf( "debug: remaining arguments are in arg=%d, "
+		        "firstn=%s, secondn=%s..\n",
+			arg, argv[arg], argv[arg+1] );
+	}
+
+	int nel = 0;
+	for( int i=arg; i<argc; i++ )
+	{
+		arr[nel++] = atoi( argv[i] );
+	}
+	arr[nel] = -1;
+	return nel;
+}
+
+
+//
+// bool isint = check_unsigned_int( char *val, int *n );
+//	Given an string val, check that there's an unsigned integer
+//	in it (after optional whitespace).  If there is a valid
+//	unsigned integer value, store that integer value in *n and
+//	return true; otherwise return false (and don't alter *n).
+bool check_unsigned_int( char *val, int *n )
+{
+	// skip whitespace in val
+	char *p;
+	for( p=val; isspace(*p); p++ )
+	{
+		/*EMPTY*/
+	}
+	if( ! isdigit(*p) ) return false;
+	*n = atoi(p);
+	return true;
+}
+
+
+//
+// bool isint = check_int( char *val, int *n );
+//	Given an string val, check that there's an integer
+//	in it (after optional whitespace).  If there is a valid
+//	integer value, store that integer value in *n and
+//	return true; otherwise return false (and don't alter *n).
+bool check_int( char *val, int *n )
+{
+	// skip whitespace in val
+	char *p;
+	for( p=val; isspace(*p); p++ )
+	{
+		/*EMPTY*/
+	}
+	int sign = 1;
+	if( *p == '+' ) p++;
+	else if( *p == '-' )
+	{
+		sign = -1;
+		p++;
+	}
+	if( ! isdigit(*p) ) return false;
+	*n = atoi(p) * sign;
+	return true;
+}
+
+
+//
+// bool ok = check_unsigned_real( char *val, double *n );
+//	Given an string val, check that there's an unsigned real
+//	in it (after optional whitespace).  If there is a valid
+//	unsigned real value, store that value in *n and
+//	return true; otherwise return false (and don't alter *n).
+bool check_unsigned_real( char *val, double *n )
+{
+	// skip whitespace in val
+	char *p;
+	for( p=val; isspace(*p); p++ )
+	{
+		/*EMPTY*/
+	}
+	if( ! isdigit(*p) ) return false;
+	*n = atof(p);
+	return true;
+}
diff --git a/challenge-214/duncan-c-white/C/args.h b/challenge-214/duncan-c-white/C/args.h
new file mode 100644
index 0000000000..df765fa21e
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/args.h
@@ -0,0 +1,12 @@
+extern bool debug;
+
+extern void process_flag_noarg( char * name, int argc, char ** argv );
+extern int process_flag_n_args( char * name, int argc, char ** argv, int n, char * argmsg );
+extern int process_flag_n_m_args( char * name, int argc, char ** argv, int min, int max, char * argmsg );
+extern void process_onenumarg_default( char * name, int argc, char ** argv, int defvalue, int * n );
+extern void process_onenumarg( char * name, int argc, char ** argv, int * n );
+extern void process_twonumargs( char * name, int argc, char ** argv, int * m, int * n );
+extern int process_listnumargs( char * name, int argc, char ** argv, int * arr, int maxel );
+extern bool check_unsigned_int( char * val, int * n );
+extern bool check_int( char * val, int * n );
+extern bool check_unsigned_real( char * val, double * n );
diff --git a/challenge-214/duncan-c-white/C/ch-1.c b/challenge-214/duncan-c-white/C/ch-1.c
new file mode 100644
index 0000000000..09c42a0e18
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/ch-1.c
@@ -0,0 +1,93 @@
+// Task 1: Rank Score
+//
+// C translation
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include "args.h"
+#include "parseints.h"
+#include "printarray.h"
+#include "rank.h"
+
+
+static int intcmp_desc( const void *a, const void *b )
+{
+	int *ap = (int *)a;
+	int *bp = (int *)b;
+	return *bp - *ap;
+}
+
+
+//
+// bool in = isin( v, list, nel );
+//	Return true iff v is in list[nel].
+//
+bool isin( int v, int *list, int nel )
+{
+	for( int i=0; i<nel; i++ )
+	{
+		if( list[i] == v ) return true;
+	}
+	return false;
+}
+
+
+int main( int argc, char **argv )
+{
+	int argno = process_flag_n_m_args( "rank-score", argc, argv,
+		1, 1000, "intlist" );
+	int nel;
+	int *list = parse_int_args( argc, argv, argno, &nel );
+
+	if( debug )
+	{
+		printf( "debug: list: " );
+		print_int_array( 60, nel, list, ',', stdout );
+		putchar( '\n' );
+	}
+
+	int sorted[nel];
+	memcpy( sorted, list, nel*sizeof(int) );
+
+	// sort in DESCENDING sorted order
+	qsort( sorted, nel, sizeof(int), &intcmp_desc );
+
+	// allocate ranks, coping with joint ranks..
+	int rank = 1;
+	int result[ nel ];
+
+	// foreach distinct value <val> in sorted order
+	for( int i=0; i<nel; i++ )
+	{
+		if( i==0 || ! isin( sorted[i], sorted, i ) )	// distinct
+		{
+			int val = sorted[i];
+			if( debug )
+			{
+				printf( "distinct value %d\n", val );
+			}
+
+			int n = 0;
+			for( int j=0; j<nel; j++ )
+			{
+				if( list[j] == val )
+				{
+					result[j] = rank;
+					n++;
+				}
+			}
+			rank+=n;
+		}
+	}
+
+	print_rank_array( 60, nel, result, ',', stdout );
+	putchar( '\n' );
+
+	free( list );
+	return 0;
+}
diff --git a/challenge-214/duncan-c-white/C/parseints.c b/challenge-214/duncan-c-white/C/parseints.c
new file mode 100644
index 0000000000..3e820eb334
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/parseints.c
@@ -0,0 +1,114 @@
+// Simple routine to parse one or more arguments,
+// looking for individual ints or comma-separated
+// lists of ints.
+// 
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include "args.h"
+#include "printarray.h"
+#include "parseints.h"
+
+typedef struct
+{
+	int nel;	// current number of elements 
+	int maxel;	// maximum number of elements allocated
+	int *list;	// malloc()d list of integers
+} intlist;
+
+
+//
+// intlist il.. then initialize il..  then:
+// add_one( element, &il );
+//	
+static void add_one( int x, intlist *p )
+{
+	if( p->nel > p->maxel )
+	{
+		p->maxel += 128;
+		p->list = realloc( p->list, p->maxel );
+		assert( p->list != NULL );
+	}
+	#if 0
+	if( debug )
+	{
+		printf( "PIA: appending %d to result at "
+			"pos %d\n", x, p->nel );
+	}
+	#endif
+	p->list[p->nel++] = x;
+}
+
+
+//
+// intlist il.. then initialize il..  then:
+// add_one_arg( argstr, &il );
+//	
+static void add_one_arg( char *argstr, intlist *p )
+{
+	int x;
+	if( !check_int(argstr,&x) )
+	{
+		fprintf( stderr, "PIA: arg %s must be int\n", argstr );
+		exit(1);
+	}
+	add_one( x, p );
+}
+
+
+//
+// int nel;
+// int *ilist = parse_int_args( argc, argv, argno, &nel );
+//	process all arguments argv[argno..argc-1], extracting either
+//	single ints or comma-separated lists of ints from those arguments,
+//	accumulate all integers in a dynarray list, storing the total number
+//	of elements in nel.  This list must be freed by the caller.
+//	Note that the list of elements used to be terminated by a -1 value,
+//	but I've commented this out from now on.
+//
+int *parse_int_args( int argc, char **argv, int argno, int *nel )
+{
+	int *result = malloc( 128 * sizeof(int) );
+	assert( result != NULL );
+	intlist il = { 0, 128, result };
+
+	#if 0
+	if( debug )
+	{
+		printf( "PIA: parsing ints from args %d..%d\n", argno, argc-1 );
+	}
+	#endif
+	for( int i=argno; i<argc; i++ )
+	{
+		assert( strlen(argv[i]) < 1024 );
+		char copy[1024];
+		strcpy( copy, argv[i] );
+		char *com;
+		char *s;
+		for( s=copy; (com = strchr(s,',')) != NULL; s=com+1 )
+		{
+			*com = '\0';
+			add_one_arg( s, &il );
+		}
+		add_one_arg( s, &il );
+	}
+
+	//add_one( -1, &il );
+
+	#if 0
+	if( debug )
+	{
+		printf( "PIA: final list is " );
+		print_int_array( 80, il.nel, il.list, ',', stdout );
+		putchar( '\n' );
+	}
+	#endif
+
+	*nel = il.nel;
+	return il.list;
+}
diff --git a/challenge-214/duncan-c-white/C/parseints.h b/challenge-214/duncan-c-white/C/parseints.h
new file mode 100644
index 0000000000..da5e145a86
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/parseints.h
@@ -0,0 +1 @@
+extern int * parse_int_args( int argc, char ** argv, int argno, int * nel );
diff --git a/challenge-214/duncan-c-white/C/printarray.c b/challenge-214/duncan-c-white/C/printarray.c
new file mode 100644
index 0000000000..ddee597df3
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/printarray.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+
+
+// print_int_array( maxw, nelements, results[], sep, outfile );
+//	format results[0..nelements-1] as a <sep> separated
+//      list onto outfile with lines <= maxw chars long.
+//	produces a whole number of lines of output - without the trailing '\n'
+void print_int_array( int maxw, int nel, int *results, char sep, FILE *out )
+{
+	int linelen = 0;
+	for( int i=0; i<nel; i++ )
+	{
+		char buf[100];
+		sprintf( buf, "%d", results[i] );
+		int len = strlen(buf);
+		if( linelen + len + 2 > maxw )
+		{
+			fputc( '\n', out );
+			linelen = 0;
+		} else if( i>0 )
+		{
+			fputc( ' ', out );
+			linelen++;
+		}
+
+		linelen += len;
+		fprintf( out, "%s", buf );
+		if( i<nel-1 )
+		{
+			fputc( sep, out );
+			linelen++;
+		}
+	}
+	//if( linelen>0 )
+	//{
+	//	fputc( '\n', out );
+	//}
+}
diff --git a/challenge-214/duncan-c-white/C/printarray.h b/challenge-214/duncan-c-white/C/printarray.h
new file mode 100644
index 0000000000..40efb83277
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/printarray.h
@@ -0,0 +1 @@
+extern void print_int_array( int maxw, int nel, int * results, char sep, FILE * out );
diff --git a/challenge-214/duncan-c-white/C/rank.c b/challenge-214/duncan-c-white/C/rank.c
new file mode 100644
index 0000000000..be697c6219
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/rank.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <string.h>
+
+
+#include "rank.h"
+
+
+// print_rank_array( maxw, nelements, results[], sep, outfile );
+//	format results[0..nelements-1] as a <sep> separated
+//      list onto outfile with lines <= maxw chars long.
+//	Replace 1 with G, 2 with S, and 3 with B.
+//	produces a whole number of lines of output.
+//
+void print_rank_array( int maxw, int nel, int *results, char sep, FILE *out )
+{
+	int linelen = 0;
+	for( int i=0; i<nel; i++ )
+	{
+		char buf[100];
+		sprintf( buf, "%d", results[i] );
+		switch( results[i] )
+		{
+		case 1: strcpy( buf, "G" ); break;
+		case 2: strcpy( buf, "S" ); break;
+		case 3: strcpy( buf, "B" ); break;
+		}
+		int len = strlen(buf);
+		if( linelen + len + 2 > maxw )
+		{
+			fputc( '\n', out );
+			linelen = 0;
+		//} else if( i>0 )
+		//{
+		//	fputc( ' ', out );
+		//	linelen++;
+		}
+
+		linelen += len;
+		fprintf( out, "%s", buf );
+		if( i<nel-1 )
+		{
+			fputc( sep, out );
+			linelen++;
+		}
+	}
+}
diff --git a/challenge-214/duncan-c-white/C/rank.h b/challenge-214/duncan-c-white/C/rank.h
new file mode 100644
index 0000000000..846d2fbde0
--- /dev/null
+++ b/challenge-214/duncan-c-white/C/rank.h
@@ -0,0 +1 @@
+extern void print_rank_array( int maxw, int nel, int * results, char sep, FILE * out );
diff --git a/challenge-214/duncan-c-white/README b/challenge-214/duncan-c-white/README
index bf3941e44d..17df43b304 100644
--- a/challenge-214/duncan-c-white/README
+++ b/challenge-214/duncan-c-white/README
@@ -1,71 +1,112 @@
-Task 1: Fun Sort
+Task 1: Rank Score
 
-You are given a list of positive integers.  Write a script to sort the
-all even integers first then all odds in ascending order.
+You are given a list of scores (>=1).
+
+Write a script to rank each score in descending order. First three will
+get medals i.e. G (Gold), S (Silver) and B (Bronze). Rest will just get
+the ranking number.
+
+Use the standard model of giving equal scores equal rank, then advancing
+that number of ranks.
 
 Example 1
 
-  Input: @list = (1,2,3,4,5,6)
-  Output: (2,4,6,1,3,5)
+  Input: @scores = (1,2,4,3,5)
+  Output: (5,4,S,B,G)
+
+  Score 1 is the 5th rank.
+  Score 2 is the 4th rank.
+  Score 4 is the 2nd rank i.e. Silver (S).
+  Score 3 is the 3rd rank i.e. Bronze (B).
+  Score 5 is the 1st rank i.e. Gold (G).
 
 Example 2
 
-  Input: @list = (1,2)
-  Output: (2,1)
+  Input: @scores = (8,5,6,7,4)
+  Output: (G,4,B,S,5)
+
+  Score 8 is the 1st rank i.e. Gold (G).
+  Score 4 is the 4th rank.
+  Score 6 is the 3rd rank i.e. Bronze (B).
+  Score 7 is the 2nd rank i.e. Silver (S).
+  Score 4 is the 5th rank.
 
 Example 3
 
-  Input: @list = (1)
-  Output: (1)
+  Input: @list = (3,5,4,2)
+  Output: (B,G,S,4)
+
+Example 4
 
-MY NOTES: sounds very easy.  Select evens; sort them; select odds; sort them,
-then append sorted lists together.
+  Input: @scores = (2,5,2,1,7,5,1)
+  Output: (4,S,4,6,G,S,6)
 
-GUEST LANGUAGE: As a bonus, I've had a go at translating ch-2.pl into C,
+MY NOTES: sounds pretty easy, although scores (high is best) and ranks (low
+is best) are a little confusing.  Even worse is joint ranks for equal scores.
+Start from the end: Gold is a label for rank 1, Single is a label for rank 2,
+Bronze is a label for rank 3.  So work out the ranks (including the nasty
+joint ranks thing) and then apply the G/S/B stuff at the end.
+
+GUEST LANGUAGE: As a bonus, I've had a go at translating ch-1.pl into C,
 look in the C/ directory for that.
 
 
-Task 2: Shortest Route
+Task 2: Collect Points
 
-You are given a list of bidirectional routes defining a network of nodes,
-as well as source and destination node numbers.  Write a script to find
-the route from source to destination that passes through fewest nodes.
+You are given a list of numbers.
+You will perform a series of removal operations. For each operation,
+you remove from the list N (N >= 1) equal and consecutive numbers,
+and add to your score N x N.
+Determine the maximum possible score.
 
 Example 1:
 
-  Input: @routes = ([1,2,6], [5,6,7])
-         $source = 1
-         $destination = 7
-
-  Output: (1,2,6,7)
+  Input: @numbers = (2,4,3,3,3,4,5,4,2)
+  Output: 23
 
-  Source (1) is part of route [1,2,6] so the journey looks like 1 -> 2 -> 6
-  then jump to route [5,6,7] and takes the route 6 -> 7.
-  So the final route is (1,2,6,7)
+  We see three 3's next to each other so let us remove that first and
+  collect 3 x 3 points.
+  So now the list is (2,4,4,5,4,2).
+  Let us now remove 5 so that all 4's can be next to each other and
+  collect 1 x 1 point.
+  So now the list is (2,4,4,4,2).
+  Time to remove three 4's and collect 3 x 3 points.
+  Now the list is (2,2).
+  Finally remove both 2's and collect 2 x 2 points.
+  So the total points collected is 9 + 1 + 9 + 4 => 23.
 
 Example 2:
 
-  Input: @routes = ([1,2,3], [4,5,6])
-         $source = 2
-         $destination = 5
+  Input: @numbers = (1,2,2,2,2,1)
+  Output: 20
 
-  Output: -1
+  Remove four 2's first and collect 4 x 4 points.
+  Now the list is (1,1).
+  Finally remove the two 1's and collect 2 x 2 points.
+  So the total points collected is 16 + 4 => 20.
 
 Example 3:
 
-  Input: @routes = ([1,2,3], [4,5,6], [3,8,9], [7,8])
-         $source = 1
-         $destination = 7
-  Output: (1,2,3,8,7)
+  Input: @numbers = (1)
+  Output: 1
+
+Example 4:
+
+  Input: @numbers = (2,2,2,1,1,2,2,2)
+  Output: 40
 
-  Source (1) is part of route [1,2,3] so the journey looks like 1 -> 2 -> 3
-  then jump to route [3,8,9] and takes the route 3 -> 8
-  then jump to route [7,8] and takes the route 8 -> 7
-  So the final route is (1,2,3,8,7)
+  Remove two 1's = 2 x 2 points.
+  Now the list is (2,2,2,2,2,2).
+  Then remove six 2's = 6 x 6 points.
 
-MY NOTES: hmmm.. weird "list of routes" data format.  Easier if we can
-convert the data into "normal" node -> list possible next nodes form.
-Shortest route means: find all routes and min() them?
+MY NOTES: hmmm.. that seems a bit tricky, in particular I can't immediately
+see whether we have do try all possible first moves (etc), or just the first
+move (or nth move more generally) with the greatest score contribution..
+Actually, eg 4 shows that we CAN'T just take the individual move with the
+greatest score contribution, cos otherwise we'd take one of the "length 3"
+sequences and pass up the "length 6" sequence that becomes available later..
+So, yes, it's a brute force "find all" type problem..
 
-GUEST LANGUAGE: I will translate ch-2.pl into C tomorrow. Run out of time
-to do it today.
+GUEST LANGUAGE: As a bonus, I will soon have a go at translating ch-2.pl
+into C, but I run out of time today.. when it's done, look in the C/
+directory for that.
diff --git a/challenge-214/duncan-c-white/perl/ch-1.pl b/challenge-214/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..fd75ff0b18
--- /dev/null
+++ b/challenge-214/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,93 @@
+#!/usr/bin/perl
+# 
+# Task 1: Rank Score
+# 
+# You are given a list of scores (>=1).
+# 
+# Write a script to rank each score in descending order. First three will
+# get medals i.e. G (Gold), S (Silver) and B (Bronze). Rest will just get
+# the ranking number.
+# 
+# Use the standard model of giving equal scores equal rank, then advancing
+# that number of ranks.
+# 
+# Example 1
+# 
+#   Input: @scores = (1,2,4,3,5)
+#   Output: (5,4,S,B,G)
+# 
+#   Score 1 is the 5th rank.
+#   Score 2 is the 4th rank.
+#   Score 4 is the 2nd rank i.e. Silver (S).
+#   Score 3 is the 3rd rank i.e. Bronze (B).
+#   Score 5 is the 1st rank i.e. Gold (G).
+# 
+# Example 2
+# 
+#   Input: @scores = (8,5,6,7,4)
+#   Output: (G,4,B,S,5)
+# 
+#   Score 8 is the 1st rank i.e. Gold (G).
+#   Score 4 is the 4th rank.
+#   Score 6 is the 3rd rank i.e. Bronze (B).
+#   Score 7 is the 2nd rank i.e. Silver (S).
+#   Score 4 is the 5th rank.
+# 
+# Example 3
+# 
+#   Input: @list = (3,5,4,2)
+#   Output: (B,G,S,4)
+# 
+# Example 4
+# 
+#   Input: @scores = (2,5,2,1,7,5,1)
+#   Output: (4,S,4,6,G,S,6)
+# 
+# MY NOTES: sounds pretty easy, although scores (high is best) and ranks (low
+# is best) are a little confusing.  Even worse is joint ranks for equal scores.
+# Start from the end: Gold is a label for rank 1, Single is a label for rank 2,
+# Bronze is a label for rank 3.  So work out the ranks (including the nasty
+# joint ranks thing) and then apply the G/S/B stuff at the end.
+# 
+# GUEST LANGUAGE: As a bonus, I've had a go at translating ch-1.pl into C,
+# look in the C/ directory for that.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Data::Dumper;
+use List::Util qw(any);
+
+my $debug=0;
+die "Usage: rank-score [--debug] intlist\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV>0;
+
+my @list = split( /,/, join(',',@ARGV) );
+
+say "debug: list: ", join(',',@list) if $debug;
+
+# distinct values in sorted order
+my %set = map { $_ => 1 } @list;
+my @distinctsortval = sort { $b <=> $a } keys %set;
+
+# allocate ranks, coping with joint ranks..
+my $rank = 1;
+my @result;
+foreach my $val (@distinctsortval)
+{
+	my @pos = grep { $list[$_] == $val } 0..$#list;
+	$result[$_] = $rank for @pos;
+	$rank += @pos;
+}
+
+# change ranks 1..3 -> G,S,B
+foreach my $v (@result)
+{
+	$v = 'G' if $v eq 1;
+	$v = 'S' if $v eq 2;
+	$v = 'B' if $v eq 3;
+}
+
+say join(',', @result);
diff --git a/challenge-214/duncan-c-white/perl/ch-2.pl b/challenge-214/duncan-c-white/perl/ch-2.pl
new file mode 100755
index 0000000000..ad6d7facf5
--- /dev/null
+++ b/challenge-214/duncan-c-white/perl/ch-2.pl
@@ -0,0 +1,159 @@
+#!/usr/bin/perl
+#
+# Task 2: Collect Points
+# 
+# You are given a list of numbers.
+# You will perform a series of removal operations. For each operation,
+# you remove from the list N (N >= 1) equal and consecutive numbers,
+# and add to your score N x N.
+# Determine the maximum possible score.
+# 
+# Example 1:
+# 
+#   Input: @numbers = (2,4,3,3,3,4,5,4,2)
+#   Output: 23
+# 
+#   We see three 3's next to each other so let us remove that first and
+#   collect 3 x 3 points.
+#   So now the list is (2,4,4,5,4,2).
+#   Let us now remove 5 so that all 4's can be next to each other and
+#   collect 1 x 1 point.
+#   So now the list is (2,4,4,4,2).
+#   Time to remove three 4's and collect 3 x 3 points.
+#   Now the list is (2,2).
+#   Finally remove both 2's and collect 2 x 2 points.
+#   So the total points collected is 9 + 1 + 9 + 4 => 23.
+# 
+# Example 2:
+# 
+#   Input: @numbers = (1,2,2,2,2,1)
+#   Output: 20
+# 
+#   Remove four 2's first and collect 4 x 4 points.
+#   Now the list is (1,1).
+#   Finally remove the two 1's and collect 2 x 2 points.
+#   So the total points collected is 16 + 4 => 20.
+# 
+# Example 3:
+# 
+#   Input: @numbers = (1)
+#   Output: 1
+# 
+# Example 4:
+# 
+#   Input: @numbers = (2,2,2,1,1,2,2,2)
+#   Output: 40
+# 
+#   Remove two 1's = 2 x 2 points.
+#   Now the list is (2,2,2,2,2,2).
+#   Then remove six 2's = 6 x 6 points.
+# 
+# MY NOTES: hmmm.. that seems a bit tricky, in particular I can't immediately
+# see whether we have do try all possible first moves (etc), or just the first
+# move (or nth move more generally) with the greatest score contribution..
+# Actually, eg 4 shows that we CAN'T just take the individual move with the
+# greatest score contribution, cos otherwise we'd take one of the "length 3"
+# sequences and pass up the "length 6" sequence that becomes available later..
+# So, yes, it's a brute force "find all" type problem..
+# 
+# GUEST LANGUAGE: As a bonus, I will soon have a go at translating ch-2.pl
+# into C, but I run out of time today.. when it's done, look in the C/
+# directory for that.
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Data::Dumper;
+use Function::Parameters;
+
+my $debug=0;
+die "Usage: collect-points [--debug] intlist\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV > 0;
+
+
+#
+# my @moves = all_possible_first_moves( @list );
+#	Find all possible first (immediate) moves, return
+#	a list of moves where each move is a [ startpos, len ] pair.
+#
+fun all_possible_first_moves( @list )
+{