imported my solutions to this week's tasks, in Perl and C as usual, few mins late

13 files changed, 834 insertions, 23 deletions

diff --git a/challenge-196/duncan-c-white/C/Makefile b/challenge-196/duncan-c-white/C/Makefile
new file mode 100644
index 0000000000..1b34ccd3b2
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/Makefile
@@ -0,0 +1,18 @@
+# Makefile rules generated by CB
+CC	= gcc
+CFLAGS	= -Wall -g
+BUILD	= ch-1 ch-2
+
+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
+ch-1.o:	ch-1.c args.h parseints.h printarray.h
+ch-2:	ch-2.o args.o parseints.o printarray.o
+ch-2.o:	ch-2.c args.h parseints.h printarray.h
+parseints.o:	parseints.c args.h parseints.h printarray.h
+printarray.o:	printarray.c
+
diff --git a/challenge-196/duncan-c-white/C/README b/challenge-196/duncan-c-white/C/README
new file mode 100644
index 0000000000..5f960417f8
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/README
@@ -0,0 +1,9 @@
+Thought I'd also have a go at translating ch-1.pl and ch-2.pl into C..
+
+Both C versions produce near-identical (non-debugging and even debugging)
+output to the Perl originals.
+
+They use several of my regular support modules:
+- a command-line argument processing module args.[ch],
+- a csvlist-of-int parsing module parseints.[ch], and
+- an int-array printing module printarray.[ch].
diff --git a/challenge-196/duncan-c-white/C/args.c b/challenge-196/duncan-c-white/C/args.c
new file mode 100644
index 0000000000..d4a2d38b9a
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/args.c
@@ -0,0 +1,207 @@
+#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 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-196/duncan-c-white/C/args.h b/challenge-196/duncan-c-white/C/args.h
new file mode 100644
index 0000000000..8844a8f9c4
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/args.h
@@ -0,0 +1,11 @@
+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_unsigned_real( char * val, double * n );
diff --git a/challenge-196/duncan-c-white/C/ch-1.c b/challenge-196/duncan-c-white/C/ch-1.c
new file mode 100644
index 0000000000..3a31e6f136
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/ch-1.c
@@ -0,0 +1,88 @@
+//
+// Task 1: Pattern 132
+// 
+// C version.
+// 
+
+#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"
+
+
+//
+// int * found = find_pat_132( arr, n );
+//	Find and return a 3-element freshly malloc()d array found[] containing
+//	the first subsequence of arr that matches the 132 rules above, or
+//	return NULL if none.
+//
+int * find_pat_132( int *arr, int n )
+{
+	for( int i=0; i<n-2; i++ )
+	{
+		for( int j=i+1; j<n-1; j++ )
+		{
+			for( int k=j+1; k<n; k++ )
+			{
+				if( arr[i] < arr[k] && arr[k] < arr[j] )
+				{
+					int *list = malloc( 3 * sizeof(int) );
+					assert( list != NULL );
+					list[0] = arr[i];
+					list[1] = arr[j];
+					list[2] = arr[k];
+					return list;
+				}
+			}
+		}
+	}
+	return NULL;
+}
+
+
+int main( int argc, char **argv )
+{
+	int argno = process_flag_n_m_args( "pattern-132", argc, argv,
+		1, 1000, "intlist" );
+
+	int nel;
+	int *list = parse_int_args( argc, argv, argno, &nel );
+
+	if( nel < 2 )
+	{
+		fprintf( stderr, "pattern-132: need a list of > 1 elements\n" );
+		exit(1);
+	}
+
+	if( debug )
+	{
+		printf( "debug: initial list: " );
+		print_int_array( 60, nel, list, ',', stdout );
+		putchar( '\n' );
+	}
+
+	if( nel < 1 )
+	{
+		fprintf( stderr, "special-numbers: nel %d must be > 0\n", nel );
+		exit(1);
+	}
+
+	int *sol = find_pat_132( list, nel );
+	printf( "(" );
+	if( sol != NULL )
+	{
+		printf( "%d, %d, %d", sol[0], sol[1], sol[2] );
+		free( sol );
+	}
+	printf( ")\n" );
+
+	free( list );
+
+	return 0;
+}
diff --git a/challenge-196/duncan-c-white/C/ch-2.c b/challenge-196/duncan-c-white/C/ch-2.c
new file mode 100644
index 0000000000..4b86b1e884
--- /dev/null
+++ b/challenge-196/duncan-c-white/C/ch-2.c
@@ -0,0 +1,131 @@
+//
+// Task 2: Range List
+// 
+// C version.
+// 
+
+#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"
+
+
+typedef char shortstr[10];	// long enough to store a-b string
+
+
+//
+// shortstr *ranges;		// dynamic array of strings
+// int nr = 0;
+// find_ranges( list, nel, &ranges, &nr );
+//	Find and return all ranges of consecutive numbers in @list.
+//	Each range is an [from,to] pair.  ranges is a dynarray, which
+//	the caller must free.
+//
+void find_ranges( int *list, int nel, shortstr **ranges, int *nr )
+{
+	shortstr *r = malloc( nel * sizeof(shortstr) );
+	assert( r != NULL );
+	*ranges = r;
+	*nr = 0;
+
+	int from = -1;
+	int to = -1;
+	for( int i=0; i<nel; i++ )
+	{
+		int item = list[i];
+		if( from == -1 )		// start first range
+		{
+			from = item;
+			to = item;
+			if( debug )
+			{
+				printf( "debug: item=%d, 1st range %d..%d\n",
+					item, from, to );
+			}
+		} else if( item == to+1 )	// extend current range
+		{
+			to++;
+			if( debug )
+			{
+				printf( "debug: item=%d, extend range %d..%d\n",
+					item, from, to );
+			}
+		} else				// finish one range, start next
+		{
+			if( to > from )		// len > 1: add range
+			{
+				shortstr s;
+				sprintf( s, "[%d,%d]", from, to );
+				strcpy( r[(*nr)++], s );
+				if( debug )
+				{
+					printf( "debug: item=%d, add range %d..%d\n",
+						item, from, to );
+				}
+			}
+			from = item;
+			to = item;
+			if( debug )
+			{
+				printf( "debug: item=%d, new range %d..%d\n",
+					item, from, to );
+			}
+		}
+	}
+	if( to > from )			// len > 1: add range
+	{
+		shortstr s;
+		sprintf( s, "[%d,%d]", from, to );
+		strcpy( r[(*nr)++], s );
+		if( debug )
+		{
+			printf( "debug: add final range %d..%d\n", from, to );
+		}
+	}
+}
+
+
+int main( int argc, char **argv )
+{
+	int argno = process_flag_n_m_args( "range-list", argc, argv,
+		1, 1000, "intlist" );
+
+	int nel;
+	int *list = parse_int_args( argc, argv, argno, &nel );
+
+	if( nel < 3 )
+	{
+		fprintf( stderr, "range-list: need at least 3 ints in list\n" );
+		exit(1);
+	}
+
+	if( debug )
+	{
+		printf( "debug: initial list: " );
+		print_int_array( 60, nel, list, ',', stdout );
+		putchar( '\n' );
+	}
+
+	shortstr *ranges;		// dynamic array of strings
+	int nr = 0;
+	find_ranges( list, nel, &ranges, &nr );
+	//printf( "nr=%d, ranges=", nr );
+	for( int i=0; i<nr; i++ )
+	{
+		if( i>0 ) printf( ", " );
+		printf( "%s", ranges[i] );
+	}
+	putchar( '\n' );
+
+	free( ranges );
+
+	free( list );
+
+	return 0;
+}
diff --git a/challenge-196/duncan-c-white/C/parseints.c b/challenge-196/duncan-c-white/C/parseints.c
new file mode 100644
index 0000000000..0fb9985633
--- /dev/null
+++ b/challenge-196/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 );
+	}
+	#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_unsigned_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 );
+	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-196/duncan-c-white/C/parseints.h b/challenge-196/duncan-c-white/C/parseints.h
new file mode 100644
index 0000000000..da5e145a86
--- /dev/null
+++ b/challenge-196/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-196/duncan-c-white/C/printarray.c b/challenge-196/duncan-c-white/C/printarray.c
new file mode 100644
index 0000000000..ddee597df3
--- /dev/null
+++ b/challenge-196/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-196/duncan-c-white/C/printarray.h b/challenge-196/duncan-c-white/C/printarray.h
new file mode 100644
index 0000000000..40efb83277
--- /dev/null
+++ b/challenge-196/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-196/duncan-c-white/README b/challenge-196/duncan-c-white/README
index 63318ee3fc..bce30687f2 100644
--- a/challenge-196/duncan-c-white/README
+++ b/challenge-196/duncan-c-white/README
@@ -1,50 +1,63 @@
-Task 1: Special Integers
+Task 1: Pattern 132
 
-You are given a positive integer, $n > 0.
+You are given a list of integers, @list.
 
-Write a script to print the count of all special integers between 1 and $n:
-An integer is special when all of its digits are unique.
+Write a script to find out subsequence that respect Pattern 132. Return
+empty array if none found.
 
-Example 1:
+Pattern 132 in a sequence (a[i], a[j], a[k]) such that i < j < k
+and a[i] < a[k] < a[j].
 
-Input: $n = 15
-Output: 14 as except 11 all other integers between 1 and 15 are spcial.
+Example 1
+
+Input:  @list = (3, 1, 4, 2)
+Output: (1, 4, 2) respect the Pattern 132.
+
+Example 2
+
+Input: @list = (1, 2, 3, 4)
+Output: () since no subsequence can be found.
+
+Example 3
+
+Input: @list = (1, 3, 2, 4, 6, 5)
+Output: (1, 3, 2) if more than one subsequence found then return the first.
 
-Example 2:
+Example 4
 
-Input: $n = 35
-Output: 32 as except 11, 22, 33 all others are special.
+Input: @list = (1, 3, 4, 2)
+Output: (1, 3, 2)
 
-MY NOTES: very easy; use a freq hash
+MY NOTES: very easy; straightforward "non-clever" code.
 
 GUEST LANGUAGE: As a bonus, I also had a go at translating ch-1.pl
 into C (look in the C directory for the translation)
 
 
-Task 2: Most Frequent Even
+Task 2: Range List
 
-You are given a list of numbers, @list.
+You are given a sorted unique integer array, @array.
 
-Write a script to find most frequent even numbers in the list. In case you
-get more than one even numbers then return the smallest even integer. For
-all other case, return -1.
+Write a script to find all possible Number Range i.e [x, y] represent
+range all integers from x and y (both inclusive).  Each subsequence
+must be of two or more contiguous integers.
 
 Example 1
 
-Input: @list = (1,1,2,6,2)
-Output: 2 as there are only 2 even numbers 2 and 6 and of those 2 appears the most.
+Input: @array = (1,3,4,5,7)
+Output: [3,5]
 
 Example 2
 
-Input: @list = (1,3,5,7)
-Output: -1 since no even numbers found in the list
+Input: @array = (1,2,3,6,7,9)
+Output: [1,3], [6,7]
 
 Example 3
 
-Input: @list = (6,4,4,6,1)
-Output: 4 since there are only two even numbers 4 and 6. They both appears the equal number of times, so pick the smallest.
+Input: @array = (0,1,2,4,5,6,8,9)
+Output: [0,2], [4,6], [8,9]
 
-MY NOTES: very easy; select even numbers; build a freq hash, sort by freqs..
+MY NOTES: simple enough state machine while we walk over the array in 1-pass.
 
 GUEST LANGUAGE: As a bonus, I also had a go at translating ch-2.pl
 into C (look in the C directory for the translation)
diff --git a/challenge-196/duncan-c-white/perl/ch-1.pl b/challenge-196/duncan-c-white/perl/ch-1.pl
new file mode 100755
index 0000000000..6d18bce65c
--- /dev/null
+++ b/challenge-196/duncan-c-white/perl/ch-1.pl
@@ -0,0 +1,80 @@
+#!/usr/bin/perl
+# 
+# Task 1: Pattern 132
+# 
+# You are given a list of integers, @list.
+# 
+# Write a script to find out the first subsequence that respect Pattern 132.
+# Return empty array if none found.
+# 
+# Pattern 132 in a sequence (a[i], a[j], a[k]) such that i < j < k
+# and a[i] < a[k] < a[j].
+# 
+# Example 1
+# 
+# Input:  @list = (3, 1, 4, 2)
+# Output: (1, 4, 2) respect the Pattern 132.
+# 
+# Example 2
+# 
+# Input: @list = (1, 2, 3, 4)
+# Output: () since no subsequence can be found.
+# 
+# Example 3
+# 
+# Input: @list = (1, 3, 2, 4, 6, 5)
+# Output: (1, 3, 2) if more than one subsequence found then return the first.
+# 
+# Example 4
+# 
+# Input: @list = (1, 3, 4, 2)
+# Output: (1, 3, 2)
+# 
+# MY NOTES: very easy; straightforward "non-clever" code.
+# 
+# GUEST LANGUAGE: As a bonus, I also had a go at translating ch-1.pl
+# into C (look in the C directory for the translation)
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Data::Dumper;
+
+my $debug=0;
+die "Usage: pattern-132 [--debug] intlist\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV>0;
+
+=pod
+
+=head2 my @sol = find_pat_132( @a );
+
+Find and return the first subsequence of @a that matches the
+132 rules above, or () if none.
+
+=cut
+sub find_pat_132
+{
+	my( @a ) = @_;
+	for( my $i=0; $i<@a-2; $i++ )
+	{
+		for( my $j=$i+1; $j<@a-1; $j++ )
+		{
+			for( my $k=$j+1; $k<@a; $k++ )
+			{
+				return @a[$i,$j,$k] if
+					$a[$i] < $a[$k] < $a[$j];
+			}
+		}
+	}
+	return ();
+}
+
+
+my @list = split( /,/, join(',',@ARGV) );
+
+die "pattern-132: need at least 3 ints in list\n" unless @list>2;
+
+my @sol = find_pat_132( @list );
+say '( '. join( ', ', @sol ) . ' )';
diff --git a/challenge-196/duncan-c-white/perl/ch-2.pl b/challenge-196/duncan-c-white/perl/ch-2.pl
new file mode 100755
index 0000000000..4616846e12
--- /dev/null
+++ b/challenge-196/duncan-c-white/perl/ch-2.pl
@@ -0,0 +1,99 @@
+#!/usr/bin/perl
+# 
+# Task 2: Range List
+# 
+# You are given a sorted unique integer array, @array.
+# 
+# Write a script to find all possible Number Range i.e [x, y] represent
+# range all integers from x and y (both inclusive).  Each subsequence
+# must be of two or more contiguous integers.
+# 
+# Example 1
+# 
+# Input: @array = (1,3,4,5,7)
+# Output: [3,5]
+# 
+# Example 2
+# 
+# Input: @array = (1,2,3,6,7,9)
+# Output: [1,3], [6,7]
+# 
+# Example 3
+# 
+# Input: @array = (0,1,2,4,5,6,8,9)
+# Output: [0,2], [4,6], [8,9]
+# 
+# MY NOTES: simple enough state machine while we walk over the array in 1-pass.
+# 
+# GUEST LANGUAGE: As a bonus, I also had a go at translating ch-2.pl
+# into C (look in the C directory for the translation)
+# 
+
+use strict;
+use warnings;
+use feature 'say';
+use Getopt::Long;
+use Function::Parameters;
+use Data::Dumper;
+
+
+my $debug=0;
+die "Usage: range-list [--debug] list(int)\n"
+	unless GetOptions( "debug"=>\$debug ) && @ARGV>0;
+
+=pod
+
+=head2 my @range = find_ranges( @list );
+
+Find and return all ranges of consecutive numbers in @list.
+Each range is an [from,to] pair.
+
+=cut
+fun find_ranges( @list )
+{
+	my @result;
+	my $from = -1;
+	my $to = -1;
+	foreach my $item (@list)
+	{
+		if( $from == -1 )		# start first range
+		{
+			$from = $item;
+			$to = $item;
+			say "debug: item=$item, 1st range $from..$to" if $debug;
+		} elsif( $item == $to+1 )	# extend current range
+		{
+			$to++;
+			say "debug: item=$item, extend range $from..$to" 
+				if $debug;
+		} else				# finish one range, start next
+		{
+			if( $to > $from )	# len > 1: add range
+			{
+				push @result, [$from,$to];
+				say "debug: item=$item, add range $from..$to"
+					if $debug;
+			}
+			$from = $item;
+			$to = $item;
+			say "debug: item=$item, new range $from..$to" if $debug;
+		}
+	}
+	if( $to > $from )			# len > 1: add range
+	{
+		push @result, [$from,$to];
+		say "debug: add final range $from..$to" if $debug;
+	}
+	return @result;
+}
+
+
+
+
+my @list = split( /,/, join( ',', @ARGV ) );
+
+die "range-list: need at least 3 ints in list\n" unless @list>2;
+
+my @range = find_ranges( @list );
+#die Dumper( \@range );
+say join( ', ', map { "[$_->[0],$_->[1]]" } @range );