3

3.py

@@ -0,0 +1,66 @@
+import sys
+
+bitstrings = []
+
+for x in sys.stdin:
+    bitstrings.append(x.rstrip())
+
+transposed_bits = zip(*bitstrings)
+
+gamma_bit = ""
+epsilon_bit = ""
+
+for bit in transposed_bits:
+    if bit.count("0") > len(bit) // 2:
+        gamma_bit += "0"
+        epsilon_bit += "1"
+    else:
+        gamma_bit += "1"
+        epsilon_bit += "0"
+
+gamma = int(gamma_bit, base=2)
+epsilon = int(epsilon_bit, base=2)
+
+print("a:", gamma * epsilon)
+
+remaining = bitstrings
+
+current_bit = 0
+while len(remaining) > 1:
+    zipped = list(zip(*remaining))
+    common_value = (
+        "1" if zipped[current_bit].count("1") >= zipped[current_bit].count("0") else "0"
+    )
+    new_bits = []
+
+    for bits in remaining:
+        if bits[current_bit] == common_value:
+            new_bits.append(bits)
+
+    remaining = new_bits
+
+    current_bit += 1
+
+
+ox_rating = int(remaining[0], base=2)
+
+remaining = bitstrings
+
+current_bit = 0
+while len(remaining) > 1:
+    zipped = list(zip(*remaining))
+    least_common_value = (
+        "0" if zipped[current_bit].count("1") >= zipped[current_bit].count("0") else "1"
+    )
+    new_bits = []
+
+    for bits in remaining:
+        if bits[current_bit] == least_common_value:
+            new_bits.append(bits)
+
+    remaining = new_bits
+
+    current_bit += 1
+
+co2_rating = int(remaining[0], base=2)
+print("b:", ox_rating * co2_rating)

AoC3/main.swift

@@ -7,5 +7,9 @@
 
 import Foundation
 
-print("Hello, World!")
+let fileContent = try! String(contentsOfFile: CommandLine.arguments[1])
+
+for line in fileContent.trimmingCharacters(in: .newlines).components(separatedBy: .newlines) {
+    
+}
 

ex3.in

@@ -0,0 +1,12 @@
+00100
+11110
+10110
+10111
+10101
+01111
+00111
+11100
+10000
+11001
+00010
+01010