코드보면 쉬운데 왤케 오래걸렸지

Author: snughnu

WEEK13/백준_1253_좋다/oliver.swift

@@ -0,0 +1,68 @@
+// 잘못된 풀이 -> 음수를 생각안함
+// let n = Int(readLine()!)!
+// let sortedNums = readLine()!.split(separator: " ").compactMap { Int($0) }.sorted()
+
+// func good(_ nums: [Int], target: Int) -> Bool {
+//     var left = 0
+//     var right = nums.count - 1
+    
+//     while left < right {
+//         let sum = nums[left] + nums[right]    
+
+//         if sum < target {
+//             left += 1
+//         } else if sum > target {
+//             right -= 1
+//         } else {
+//             return true
+//         }
+//     }
+
+//     return false
+// }
+
+// var result = 0
+// for i in 2..<n {
+//     let nums = Array(sortedNums[0..<i])
+
+//     if good(nums, target: sortedNums[i]) {
+//         result += 1
+//     }
+// }
+// print(result)
+
+let n = Int(readLine()!)!
+let nums = readLine()!.split(separator: " ").compactMap { Int($0) }.sorted()
+
+var result = 0
+
+for targetIndex in 0..<n {
+    var left = 0
+    var right = n-1
+
+    while left < right {
+        if left == targetIndex {
+            left += 1
+            continue
+        }
+
+        if right == targetIndex {
+            right -= 1
+            continue
+        }
+
+        let sum = nums[left] + nums[right]
+        let target = nums[targetIndex]
+
+        if sum < target {
+            left += 1
+        } else if sum > target {
+            right -= 1
+        } else {
+            result += 1
+            break
+        }
+    }
+}
+
+print(result)