solve 3Sum

Author: delight010

3sum/delight010.swift

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+class Solution {
+    func threeSum(_ nums: [Int]) -> [[Int]] {
+        let nums = nums.sorted()
+        var answer: Set<[Int]> = []
+        for (index, num) in nums.enumerated() {
+            var leftIndex = index + 1
+            var rightIndex = nums.endIndex - 1
+            while leftIndex < rightIndex {
+                let sum = num + nums[leftIndex] + nums[rightIndex]
+                if sum == 0 {
+                    answer.insert([num, nums[leftIndex], nums[rightIndex]])
+                    leftIndex += 1
+                    rightIndex -= 1
+                } else if sum < 0 {
+                    leftIndex += 1
+                } else if sum > 0 {
+                    rightIndex -= 1
+                }
+            }
+        }
+        
+        return Array(answer)
+    }
+}
+