feat: contains-duplicate

Author: changchanghwang

contains-duplicate/changchanghwang.go

@@ -0,0 +1,13 @@
+// Time complexity, O(n)
+// Space complexity, O(n)
+func containsDuplicate(nums []int) bool {
+	hashMap := map[int]bool{}
+	for _, num := range nums {
+		if hashMap[num] {
+			return true
+		} else {
+			hashMap[num] = true
+		}
+	}
+	return false
+}