leetcode [217]

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Example 1:
Input: nums = [1,2,3,1]
Output: true

Example 2:
Input: nums = [1,2,3,4]
Output: false

Example 3:
Input: nums = [1,1,1,3,3,4,3,2,4,2]
Output: true

자바스크립트 set은 유일한 값만 저장

var containsDuplicate = function(nums) {
    var filter = new Set();
    for (let i = 0; i < nums.length; i++) {
        filter.add(nums[i]);
    }
    if (filter.size == nums.length) {
        return false;
    } else {
        return true;
    }
};