index.js

/*
 * @lc app=leetcode id=217 lang=javascript
 *
 * [217] Contains Duplicate
 *
 * https://leetcode.com/problems/contains-duplicate/description/
 *
 * algorithms
 * Easy (50.52%)
 * Total Accepted:    309.4K
 * Total Submissions: 606.1K
 * Testcase Example:  '[1,2,3,1]'
 *
 * Given an array of integers, find if the array contains any duplicates.
 * 
 * Your function should return true if any value appears at least twice in the
 * array, and it should return false if every element is distinct.
 * 
 * Example 1:
 * 
 * 
 * Input: [1,2,3,1]
 * Output: true
 * 
 * Example 2:
 * 
 * 
 * Input: [1,2,3,4]
 * Output: false
 * 
 * Example 3:
 * 
 * 
 * Input: [1,1,1,3,3,4,3,2,4,2]
 * Output: true
 * 
 */
/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    const hashMap = {};
    for (let i = 0; i < nums.length; i++) {
        const num = nums[i];
        if (hashMap[num]) {
            return true;
        }
        hashMap[num] = true;
    }
    return false;
};

console.log(containsDuplicate([1,1,1,3,3,4,3,2,4,2]));

module.exports = {
    id:'217',
    title:'Contains Duplicate',
    url:'https://leetcode.com/problems/contains-duplicate/description/',
    difficulty:'Easy',
}