contains duplicate solution

Author: RiaOh

contains-duplicate/RiaOh.js

@@ -0,0 +1,15 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+var containsDuplicate = function (nums) {
+  let count = [nums[0]];
+  for (let i = 1; i < nums.length; i++) {
+    if (count.includes(nums[i])) {
+      return true;
+    } else {
+      count.push(nums[i]);
+    }
+  }
+  return false;
+};