Add solution for day 3

AoC2021/code/AoC03.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+import sys
+
+def inverted(i):
+    if i == 0:
+        return 1
+    else:
+        return 0
+
+def filter(lis, pos, i):
+    if len(lis) == 1:
+        return lis
+    if sum([b[pos] for b in lis]) >= sum([inverted(b[pos]) for b in lis]):
+        val = i
+    else:
+        val = inverted(i)
+
+    return [i for i in lis if i[pos] == val]
+
+if __name__ == '__main__':
+    lines = open(sys.argv[1]).readlines()
+    
+    bins = [[int(i) for i in list(l.strip('\n'))] for l in lines]
+
+    # challenge 1
+    lis = [0] * len(bins[0])
+
+    for i in range(len(bins[0])):
+        lis[i] = sum([b[i] for b in bins])
+    
+    g = ''
+    e = ''
+
+    for i in range(len(bins[0])):
+        if lis[i] > 0.5 * len(lines):
+            g += '1'
+            e += '0'
+        else:
+            g += '0'
+            e += '1'
+
+    gamma = int(g, 2)
+    eps = int(e,2)
+
+    res1 = str(gamma * eps)
+    print("challenge 1:" + res1 + "\n")
+
+    ox = bins
+    co2 = bins
+
+    # challenge 2
+    for i in range(len(bins[0])):
+        ox = filter(ox, i, 1)
+        co2 = filter(co2, i, 0)
+    
+    oxr = int(''.join(str(i) for i in ox[0]), 2)
+    csr = int(''.join(str(i) for i in co2[0]), 2)
+
+    res2 = str(oxr * csr)
+    print("challenge 2:" + res2 + "\n")
+