perl solution for challenge 75 task 1

first draft

1 files changed, 73 insertions, 0 deletions

diff --git a/challenge-075/walt-mankowski/perl/ch-1.pl b/challenge-075/walt-mankowski/perl/ch-1.pl
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+#!/usr/bin/env perl
+use strict;
+use warnings;
+use feature qw(:5.32);
+use experimental qw(signatures);
+
+# TASK #1 › Coins Sum
+# Submitted by: Mohammad S Anwar
+#
+# You are given a set of coins @C, assuming you have infinite amount of each coin in the set.
+#
+# Write a script to find how many ways you make sum $S using the coins from the set @C.
+# Example:
+#
+# Input:
+#     @C = (1, 2, 4)
+#     $S = 6
+#
+# Output: 6
+# There are 6 possible ways to make sum 6.
+# a) (1, 1, 1, 1, 1, 1)
+# b) (1, 1, 1, 1, 2)
+# c) (1, 1, 2, 2)
+# d) (1, 1, 4)
+# e) (2, 2, 2)
+# f) (2, 4)
+
+my $s = shift @ARGV;
+my @c = @ARGV;
+my @solutions;
+
+my @cnt = map {0} 0..$#c;
+my $i = $#c;
+while (1) {
+    my $val = value(\@c, \@cnt);
+    if ($val >= $s) {
+        if ($val == $s) {
+            my @tmp = @cnt;
+            push @solutions, \@tmp;
+        }
+
+        # rotate "odometer"
+        $cnt[$#c] = 0;
+        my $j = $#c - 1;
+        $cnt[$j]++;
+        while ($j >= 0 && value(\@c, \@cnt) > $s) {
+            $cnt[$j] = 0;
+            $j--;
+            $cnt[$j]++;
+        }
+        last if $j < 0;
+    } else {
+        $cnt[$#c]++;
+    }
+}
+
+# print out the solutions
+say "There are " . scalar @solutions . " ways to make sum $s";
+for my $sol (@solutions) {
+    my @tmp;
+    for my $i (0..$#c) {
+        push @tmp, $c[$i] for 0..$sol->[$i]-1;
+    }
+    say "@tmp";
+}
+
+sub value($c, $cnt) {
+    my $sum = 0;
+    for my $i (0..$#$c) {
+        $sum += $c->[$i] * $cnt->[$i];
+    }
+    return $sum;
+}