Initial commit

day9/main.swift

@@ -0,0 +1,45 @@
+import Foundation
+
+let input = loadData(day: 9)
+let scanner = Scanner(string: input)
+
+let numbers = scanner.integers()!
+
+var weakness: Int? = nil
+outer: for i in 25..<numbers.count {
+    let search = numbers[i]
+
+    for j in (i - 25)..<i {
+        for k in j..<i {
+            if search == numbers[j] + numbers[k] {
+                continue outer
+            }
+        }
+    }
+
+    print("first which is not sum", i, search)
+    weakness = search
+    break
+}
+
+
+guard let weakness = weakness else { fatalError("No weakness found") }
+
+outer: for i in 0..<numbers.count {
+    var sum = 0
+    var min = Int.max
+    var max = Int.min
+    for j in (i+1)..<numbers.count {
+        let n = numbers[j]
+        sum += n
+        if n < min { min = n }
+        if n > max { max = n }
+        if sum == weakness {
+            print(min + max)
+            break outer
+        }
+        if sum > weakness {
+            break
+        }
+    }
+}