Challenge 285 solutions by Packy Anderson

  * Raku that maybe looks like Raku, but mostly like Perl
  * Perl
  * Python that definitely looks like Perl
  * Elixir

1 Blog post

1 files changed, 68 insertions, 0 deletions

diff --git a/challenge-285/packy-anderson/python/ch-2.py b/challenge-285/packy-anderson/python/ch-2.py
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+++ b/challenge-285/packy-anderson/python/ch-2.py
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+#!/usr/bin/env python
+
+from functools import cache
+
+# establish the values of the coins
+types = { 50: 'HD', 25: 'Q', 10: 'D', 5: 'N', 1: 'P' }
+
+# make a sorted list of coin values
+values = sorted(types.keys(), reverse=True)
+
+def formatCoin(coin, count):
+  return f"{count}{coin}" if count > 1 else coin
+          
+@cache
+def makeChange(amount, exclude = 0):
+  output = []
+  for value in values:
+    # if this type of coin is worth more
+    # than the total, we can't use it
+    if value > amount:
+      continue
+
+    # if we're excluding this coin value or greater, skip it
+    if exclude and value >= exclude:
+      continue
+
+    coin = types[value] # get the coin name
+
+    if value == 1:
+      # pennies are easy!
+      output.append( formatCoin(coin, amount) )
+    else:
+      # loop from max number of this coin we can use down to 1
+      for count in range(int(amount / value), 0, -1):
+        # figure out how much change we need after we've used
+        # $count many of coin $coin
+        left = amount - (count * value)
+
+        if left > 0: # we need more change
+          # make a recursive call to get the combinations
+          # for that remaining amount, excluding any coins
+          # of equal or greater value to $value
+          combinations = makeChange(left, value)
+          for combo in combinations:
+            this_coin = formatCoin(coin, count)
+            output.append(" + ".join([this_coin, combo]))
+        else: # this is exact change!
+          output.append( formatCoin(coin, count) )
+  return output
+
+def solution(amount):
+  print(f'Input: $amount = {amount}')
+  ways = makeChange(amount)
+  print(f'Output: {len(ways)}')
+  print('')
+  i = 0
+  for c in ways:
+    i += 1
+    print(f'{i}: {c}')
+
+print('Example 1:')
+solution(9)
+
+print('\nExample 2:')
+solution(15)
+
+print('\nExample 3:')
+solution(100)