Add BASIC solution

6 files changed, 223 insertions, 20 deletions

diff --git a/challenge-206/paulo-custodio/basic/ch-1.bas b/challenge-206/paulo-custodio/basic/ch-1.bas
new file mode 100644
index 0000000000..cce224cdb5
--- /dev/null
+++ b/challenge-206/paulo-custodio/basic/ch-1.bas
@@ -0,0 +1,100 @@
+' Challenge 206
+'
+' Task 1: Shortest Time
+' Submitted by: Mohammad S Anwar
+'
+' You are given a list of time points, at least 2, in the 24-hour clock format HH:MM.
+'
+' Write a script to find out the shortest time in minutes between any two time points.
+' Example 1
+'
+' Input: @time = ("00:00", "23:55", "20:00")
+' Output: 5
+'
+' Since the difference between "00:00" and "23:55" is the shortest (5 minutes).
+'
+' Example 2
+'
+' Input: @array = ("01:01", "00:50", "00:57")
+' Output: 4
+'
+' Example 3
+'
+' Input: @array = ("10:10", "09:30", "09:00", "09:55")
+' Output: 15
+
+dim mins() as integer
+
+' parse hours:minutes, return minutes
+function parse_minutes(s as string) as integer
+    dim i as integer, hours as integer, minutes as integer
+
+    'parse hours
+    i=1
+    do while i<=len(s) and mid(s,i,1)>="0" and mid(s,i,1)<="9"
+        i=i+1
+    loop
+    hours=val(left(s,i))
+    if mid(s,i,1)=":" then i=i+1
+    s=mid(s,i)
+
+    'parse minutes
+    do while i<=len(s) and mid(s,i,1)>="0" and mid(s,i,1)<="9"
+        i=i+1
+    loop
+    minutes=val(left(s,i))
+    parse_minutes=60*hours+minutes
+end function
+
+' collect arguments
+sub collect_args(mins() as integer)
+    dim i as integer
+
+    i=0
+    do while command(i+1)<>""
+        redim preserve mins(i) as integer
+        mins(i)=parse_minutes(command(i+1))
+        i=i+1
+    loop
+end sub
+
+' sort array
+sub sort(mins() as integer)
+    dim i as integer, j as integer, n as integer
+
+    for i=lbound(mins) to ubound(mins)-1
+        for j=i+1 to ubound(mins)
+            if mins(i)>mins(j) then
+                n=mins(i): mins(i)=mins(j): mins(j)=n
+            end if
+        next
+    next
+end sub
+
+' prepare data for check - sort and add first+24hours to end
+sub setup_data(mins() as integer)
+    dim i as integer
+
+    collect_args mins()
+    sort mins()
+    i=ubound(mins)
+    redim preserve mins(i+1) as integer
+    mins(i+1)=mins(0)+24*60
+end sub
+
+
+' get minimum interval
+function get_min_interval(mins() as integer) as integer
+    dim i as integer, min as integer
+
+    min=mins(ubound(mins))-mins(0)
+    for i=0 to ubound(mins)-1
+        if mins(i+1)-mins(i)<min then
+            min=mins(i+1)-mins(i)
+        end if
+    next
+    get_min_interval=min
+end function
+
+setup_data mins()
+print get_min_interval(mins())
diff --git a/challenge-206/paulo-custodio/basic/ch-2.bas b/challenge-206/paulo-custodio/basic/ch-2.bas
new file mode 100644
index 0000000000..7a5bbfd7a0
--- /dev/null
+++ b/challenge-206/paulo-custodio/basic/ch-2.bas
@@ -0,0 +1,111 @@
+' Challenge 206
+'
+' Task 2: Array Pairings
+' Submitted by: Mohammad S Anwar
+'
+' You are given an array of integers having even number of elements..
+'
+' Write a script to find the maximum sum of the minimum of each pairs.
+' Example 1
+'
+' Input: @array = (1,2,3,4)
+' Output: 4
+'
+' Possible Pairings are as below:
+' a) (1,2) and (3,4). So min(1,2) + min(3,4) => 1 + 3 => 4
+' b) (1,3) and (2,4). So min(1,3) + min(2,4) => 1 + 2 => 3
+' c) (1,4) and (2,3). So min(1,4) + min(2,3) => 2 + 1 => 3
+'
+' So the maxium sum is 4.
+'
+' Example 2
+'
+' Input: @array = (0,2,1,3)
+' Output: 2
+'
+' Possible Pairings are as below:
+' a) (0,2) and (1,3). So min(0,2) + min(1,3) => 0 + 1 => 1
+' b) (0,1) and (2,3). So min(0,1) + min(2,3) => 0 + 2 => 2
+' c) (0,3) and (2,1). So min(0,3) + min(2,1) => 0 + 1 => 1
+'
+' So the maximum sum is 2.
+
+' append number to list
+sub push_elem(nums() as integer, n as integer)
+    dim i as integer
+
+    i=ubound(nums)
+    redim preserve nums(i+1) as integer
+    nums(i+1)=n
+end sub
+
+' remove number from list
+sub del_elem(nums() as integer, idx as integer)
+    dim i as integer
+
+    for i=idx to ubound(nums)-1
+        nums(i)=nums(i+1)
+    next
+    if ubound(nums)=0 then
+        erase nums
+    else
+        redim preserve nums(ubound(nums)-1) as integer
+    end if
+end sub
+
+' copy list
+sub copy_list(src() as integer, dst() as integer)
+    dim i as integer
+
+    redim dst(ubound(src)) as integer
+    for i=0 to ubound(src)
+        dst(i)=src(i)
+    next
+end sub
+
+' collect arguments
+sub collect_args(nums() as integer)
+    dim i as integer
+
+    i=0
+    do while command(i+1)<>""
+        push_elem nums(),val(command(i+1))
+        i=i+1
+    loop
+end sub
+
+' compute maximum sum of minimum of each pair
+sub compute_pairs_max(byref max as integer, set() as integer, pending() as integer)
+    dim i as integer, j as integer, sum as integer, n as integer
+
+    if ubound(pending)<0 then   ' compute sum, set max
+        sum=0
+        for i=0 to ubound(set) step 2
+            if set(i)<set(i+1) then n=set(i) else n=set(i+1)
+            sum=sum+n
+        next
+        if sum>max then max=sum
+    else                        ' extract each pair and recurse
+        for i=0 to ubound(pending)-1
+            for j=i+1 to ubound(pending)
+                dim new_set() as integer
+                dim new_pending() as integer
+
+                copy_list set(), new_set()
+                push_elem new_set(), pending(i)
+                push_elem new_set(), pending(j)
+
+                copy_list pending(), new_pending()
+                del_elem new_pending(), j
+                del_elem new_pending(), i
+
+                compute_pairs_max max, new_set(), new_pending()
+            next
+        next
+    end if
+end sub
+
+dim empty() as integer, nums() as integer, max as integer
+collect_args nums()
+compute_pairs_max max, empty(), nums()
+print max
diff --git a/challenge-206/paulo-custodio/c/ch-1.c b/challenge-206/paulo-custodio/c/ch-1.c
index abb788e056..10e7e64ece 100644
--- a/challenge-206/paulo-custodio/c/ch-1.c
+++ b/challenge-206/paulo-custodio/c/ch-1.c
@@ -56,11 +56,9 @@ int main(int argc, char* argv[]) {
 
     int min = items[num_items-1] - items[0];
     for (int i = 0; i < num_items-1; i++) {
-        for (int j = i+1; j < num_items; j++) {
-            int n = items[j] - items[i];
-            if (n < min)
-                min = n;
-        }
+        int n = items[i+1] - items[i];
+        if (n < min)
+            min = n;
     }
 
     printf("%d\n", min);
diff --git a/challenge-206/paulo-custodio/cpp/ch-1.cpp b/challenge-206/paulo-custodio/cpp/ch-1.cpp
index c866da59c5..de714209d8 100644
--- a/challenge-206/paulo-custodio/cpp/ch-1.cpp
+++ b/challenge-206/paulo-custodio/cpp/ch-1.cpp
@@ -56,11 +56,9 @@ int main(int argc, char* argv[]) {
 
     int min = items.back() - items.front();
     for (size_t i = 0; i < items.size() - 1; i++) {
-        for (size_t j = i + 1; j < items.size(); j++) {
-            int n = items[j] - items[i];
-            if (n < min)
-                min = n;
-        }
+        int n = items[i+1] - items[i];
+        if (n < min)
+            min = n;
     }
 
     std::cout << min << std::endl;
diff --git a/challenge-206/paulo-custodio/forth/ch-1.fs b/challenge-206/paulo-custodio/forth/ch-1.fs
index b8115de9f2..5d210fad00 100644
--- a/challenge-206/paulo-custodio/forth/ch-1.fs
+++ b/challenge-206/paulo-custodio/forth/ch-1.fs
@@ -91,12 +91,10 @@
 : compute-minimum-interval ( -- minutes )
     24 60 *                         ( min )
     num_items 1- 0 DO
-        num_items I 1+ DO
-            I items[] @
-            J items[] @
-            -
-            MIN
-        LOOP
+        I 1+ items[] @
+        I items[] @
+        -
+        MIN
     LOOP
 ;
 
diff --git a/challenge-206/paulo-custodio/perl/ch-1.pl b/challenge-206/paulo-custodio/perl/ch-1.pl
index 6d0bb7cf05..fadba97c6a 100644
--- a/challenge-206/paulo-custodio/perl/ch-1.pl
+++ b/challenge-206/paulo-custodio/perl/ch-1.pl
@@ -32,10 +32,8 @@ my @in = sort { $a <=> $b } map { minutes($_) } @ARGV;
 push @in, $in[0] + minutes("24:00");
 my $min = $in[-1] - $in[0];
 for my $i (0..$#in-1) {
-    for my $j ($i+1..$#in) {
-        my $n = $in[$j] - $in[$i];
-        $min = $n if $n < $min;
-    }
+    my $n = $in[$i+1] - $in[$i];
+    $min = $n if $n < $min;
 }
 say $min;