hm i wonder if i will end up liking python for ao/algos more than go...

2024/day07/day07.py

@@ -0,0 +1,60 @@
+def day7(input: str, part: int) -> int:
+    ans: int = 0
+
+    lines = input.splitlines()
+    for line in lines:
+        parts = line.split(": ")
+        target = int(parts[0])
+        nums = [int(x) for x in parts[1].split(" ")]
+
+        if recurse(part, nums, target, 0, 0):
+            ans += target
+
+    return ans
+
+
+# brute force all the combinations and return True early if the target is made using all elements of nums array
+def recurse(part: int, nums: list[int], target: int, current: int, index: int) -> bool:
+    if target < current:
+        return False
+
+    if index == len(nums) and current == target:
+        return True
+    if index == len(nums) and current != target:
+        return False
+
+    if index == 0:
+        current = 1
+    multiply_result = recurse(part, nums, target, current * nums[index], index + 1)
+    if multiply_result:
+        return True
+
+    # attempt concatenation operation for part 2
+    if part == 2:
+        concat_num = int(str(current) + str(nums[index]))
+        concat_result = recurse(part, nums, target, concat_num, index + 1)
+        if concat_result:
+            return True
+
+    if index == 0:
+        current = 0
+    return recurse(part, nums, target, current + nums[index], index + 1)
+
+
+example = """190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20"""
+
+input = open("input.txt").read()
+
+print(f"part1 example: {day7(example,1)} want 3749")
+print(f"part1: {day7(input,1)} want 66343330034722")
+
+print(f"part2 example: {day7(example,2)} want 11387")
+print(f"part2: {day7(input,2)} want 637696070419031")  # a bit slow but not bad