Solution to problem 3 part 1 in Python

src/Year_2021/P3.py

@@ -0,0 +1,91 @@
+# --- Day 3: Binary Diagnostic ---
+
+# The submarine has been making some odd creaking noises, so you ask it to
+# produce a diagnostic report just in case.
+
+# The diagnostic report (your puzzle input) consists of a list of binary
+# numbers which, when decoded properly, can tell you many useful things about
+# the conditions of the submarine. The first parameter to check is the power
+# consumption.
+
+# You need to use the binary numbers in the diagnostic report to generate two
+# new binary numbers (called the gamma rate and the epsilon rate). The power
+# consumption can then be found by multiplying the gamma rate by the epsilon
+# rate.
+
+# Each bit in the gamma rate can be determined by finding the most common bit
+# in the corresponding position of all numbers in the diagnostic report. For
+# example, given the following diagnostic report:
+
+# 00100
+# 11110
+# 10110
+# 10111
+# 10101
+# 01111
+# 00111
+# 11100
+# 10000
+# 11001
+# 00010
+# 01010
+
+# Considering only the first bit of each number, there are five 0 bits and
+# seven 1 bits. Since the most common bit is 1, the first bit of the gamma rate
+# is 1.
+
+# The most common second bit of the numbers in the diagnostic report is 0, so
+# the second bit of the gamma rate is 0.
+
+# The most common value of the third, fourth, and fifth bits are 1, 1, and 0,
+# respectively, and so the final three bits of the gamma rate are 110.
+
+# So, the gamma rate is the binary number 10110, or 22 in decimal.
+
+# The epsilon rate is calculated in a similar way; rather than use the most
+# common bit, the least common bit from each position is used. So, the epsilon
+# rate is 01001, or 9 in decimal. Multiplying the gamma rate (22) by the
+# epsilon rate (9) produces the power consumption, 198.
+
+# Use the binary numbers in your diagnostic report to calculate the gamma rate
+# and epsilon rate, then multiply them together. What is the power consumption
+# of the submarine? (Be sure to represent your answer in decimal, not binary.)
+
+from collections import Counter
+
+with open("files/P3.txt", "r") as f:
+    diagnostics = [number for number in f.read().strip().split()]
+
+
+def part_1() -> None:
+    # holding each bit in a different key
+    bits_dic = {}
+    for i in range(12):
+        bits_dic[i] = []
+
+    [
+        bits_dic[idx].append(val)
+        for number in diagnostics
+        for idx, val in enumerate(number)
+    ]
+
+    # get bit number, and ocurrences of zeros and ones
+    res = [(k, Counter(v).most_common()) for k, v in bits_dic.items()]
+
+    gamma_bin_str = [
+        mcb[0] if mcb[1] > lcb[1] else lcb[0] if mcb[1] < lcb[1] else None
+        for k, (mcb, lcb) in res
+    ]
+    epsilon_bin_str = [
+        lcb[0] if mcb[1] > lcb[1] else mcb[0] if mcb[1] < lcb[1] else None
+        for k, (mcb, lcb) in res
+    ]
+
+    gamma = int("".join(gamma_bin_str), 2)
+    epsilon = int("".join(epsilon_bin_str), 2)
+
+    print(f"Power consumption is {gamma*epsilon}")
+
+
+if __name__ == "__main__":
+    part_1()