solve

Author: sonjh1217

two-sum/sonjh1217.swift

@@ -0,0 +1,15 @@
+class Solution {
+    // time O(n) / space O(n)
+    func twoSum(_ nums: [Int], _ target: Int) -> [Int] {
+        var indicesByCounters = [Int: Int]()
+        for (i, num) in nums.enumerated() { 
+            if let index = indicesByCounters[num] {
+                return [index, i]
+            }
+
+            indicesByCounters[target - num] = i
+        }
+
+        return []
+    }
+}