feat: solve contains-duplicate

Author: sujeong-dev

contains-duplicate/sujeong-dev.js

@@ -0,0 +1,27 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+
+// for loof: O(n)
+var containsDuplicate = function (nums) {
+  let indices = {};
+  nums.forEach((num, index) => {
+    indices[num] = index;
+  });
+
+  for (let i = 0; i < nums.length; i++) {
+    if (nums[i] in indices && indices[nums[i]] !== i) return true;
+  }
+
+  return false;
+};
+
+// size 속성: O(1)
+var containsDuplicate = function (nums) {
+  const indices = new Set(nums);
+
+  if (indices.size !== nums.length) return true;
+
+  return false;
+};