another day of coding

17/part2.py

@@ -0,0 +1,51 @@
+#!/usr/bin/python
+
+import re
+
+RE_INGRADIENT_INFO = re.compile(r'^(.*): capacity (-?\d+), durability (-?\d+), flavor (-?\d+), texture (-?\d+), calories (-?\d+)$')
+
+
+def read_file(filename):
+    file = open(filename, 'r')
+    while True:
+        line = file.readline()
+        if not line:
+            break
+        yield line
+
+
+def bottle_usage_positions(minCount, maxCount, pos, usage):
+    if pos == len(usage):
+        yield usage
+        return
+
+    for x in range(minCount, maxCount+1):
+        usage[pos] = x
+        for b in bottle_usage_positions(minCount, maxCount, pos+1, usage):
+            yield b
+    usage[pos] = minCount
+
+def calculate_liters(bottles, usage):
+    sum = 0
+    bottles_used = 0
+    for x in range(len(bottles)):
+        sum += bottles[x] * usage[x]
+        bottles_used += usage[x]
+    return (sum, bottles_used)
+
+
+def main():
+    input = 150
+    bottles = []
+    bottle_usage = []
+    for line in read_file('input'):
+        bottles.append(int(line))
+        bottle_usage.append(0)
+
+    for usage in bottle_usage_positions(0, 1, 0, bottle_usage):
+        (litres, used) = calculate_liters(bottles, usage)
+        if litres == input:
+            print used
+
+if __name__ == "__main__":
+    main()