solved day 7 part 1

2024/day7/main.py

@@ -0,0 +1,66 @@
+import re
+
+with open('input.text', 'r') as file:
+    data: list[str] = file.readlines()
+
+
+class Equation:
+    result: int
+    constants: list[int]
+
+    def __init__(self, result: int, constants: list[int]):
+        self.result = result
+        self.constants = constants
+
+    def is_valid_eq(self, eq: str) -> bool:
+        tokens: list[str] = re.findall('\d+|\+|\*', eq)
+
+        r = None
+        add = True
+        for token in tokens:
+            if not r and token.isnumeric():
+                r = int(token)
+            elif token == '+':
+                add = True
+            elif token == '*':
+                add = False
+            elif add:
+                r += int(token)
+            elif not add:
+                r *= int(token)
+
+        return r == self.result
+     
+    def is_valid(self, s: str | None) -> bool:
+        if s == None:
+            s = ''
+            for c in self.constants:
+                s += (str(c) + ' ')
+            return self.is_valid(s[:-1])
+        elif ' ' in s:
+            s1 = s.replace(' ', '+', 1)
+            s2 = s.replace(' ', '*', 1)
+            return self.is_valid(s1) or self.is_valid(s2)
+        else:
+            return self.is_valid_eq(s)
+
+
+equations: list[Equation] = []
+
+# Parse input
+for line in data:
+    if ':' in line:
+        result, constants = line.split(':')
+        result = int(result)
+        constants = [int(n) for n in constants.strip().split(' ')]
+        equations.append(Equation(result, constants))
+
+# Part 1
+total = 0
+for equation in equations:
+    if equation.is_valid(None):
+        total += equation.result
+
+print(f'Part 1: {total}')
+
+