2020 AoC, Days 1-4

2020/Day 1/Solution.py

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+target = 2020
+input_file = "/tmp/aocinput"
+
+def find_sum_of_two():
+    large_n = []
+    small_n = []
+
+    with open(input_file) as file:
+        line = file.readline()
+        while line and line != "\n":
+            halftarget_count = 0
+
+            number = int(line)
+            if number > target/2:
+                large_n.append(number)
+            elif number == target/2:
+                halftarget_count += 1
+            else:
+                small_n.append(number)
+
+            if halftarget_count == 2:
+                print(f"Found a sum : {target/2}*2 = {target}\nAnswer is {(target/2)**2}")
+                break
+
+            line = file.readline()
+
+    for big_one in large_n:
+        complement = target-big_one
+        if complement in small_n:
+            print(f"Found a sum : {big_one}+{complement} = {target}\nAnswer is {big_one*complement}")
+            return
+
+    print("No sum found that can reach {target}")
+
+def sum_search(target_sum, inputs):
+    lower = []
+    upper = []
+
+    for num in inputs:
+        if num < target_sum/2:
+            lower.append(num)
+        else:
+            upper.append(num)
+
+    search_list = lower if len(lower) < len(upper) else upper
+    iter_list = upper if len(lower) < len(upper) else lower
+
+    for num in iter_list:
+        if target_sum - num in search_list:
+            return num, target_sum-num
+
+    return False
+
+
+def find_sum_of_three():
+    data = []
+    subtracted_to_target = []
+    with open(input_file) as file:
+        line = file.readline()
+        while line and line != "\n":
+            data.append(int(line))
+            subtracted_to_target.append((target-data[-1],data[-1]))
+
+            line = file.readline()
+
+    data.sort()
+
+    for sub_target in subtracted_to_target:
+        result = sum_search(sub_target[0],data)
+        if result:
+            print(f"Sum found : {result[0]}+{result[1]}+{sub_target[1]} = {target}\nResult is {result[0]*result[1]*sub_target[1]}")
+            return
+
+    print("No sum found")
+
+