day 7 puzzle 1

src/day7/puzzle1.typ

@@ -0,0 +1,42 @@
+#import "/src/utils.typ": *
+
+#let solveable(values, target) = {
+  if values.len() == 1 {
+    return values.last() == target
+  }
+
+  let values = values
+  let v = values.pop()
+  if calc.rem(target, v) == 0 {
+    if solveable(values, target / v) {
+      return true
+    }
+  }
+  if v > target {
+    return false
+  }
+
+  return solveable(values, target - v)
+}
+
+#let solve(input) = {
+  let equations = input.split("\n")
+
+  let total = 0
+  for equation in equations {
+    let (target, values) = equation.split(": ")
+    target = int(target)
+    values = values.split(" ").map(int)
+
+    if solveable(values, target) {
+      total += target
+    }
+  }
+  return total
+}
+
+#show-puzzle(
+  7, 1,
+  solve,
+  example: 3749
+)