217. Contains Duplicate
217. Contains Duplicate
题目
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
Constraints:
1 <= nums.length <= 10^5
-10^9 <= nums[i] <= 10^9
题目大意
如果数组里面有重复数字就输出 true
,否则输出 flase
。
解题思路
用 map
判断即可。
代码
/**
* @param {number[]} nums
* @return {boolean}
*/
var containsDuplicate = function (nums) {
const map = new Map();
for (let item of nums) {
if (map.has(item)) return true;
map.set(item, 1);
}
return false;
};
相关题目
相关题目
- [219. 存在重复元素 II](./0219.md)
- [220. 存在重复元素 III](https://leetcode.com/problems/contains-duplicate-iii)
- [2357. 使数组中所有元素都等于零](https://leetcode.com/problems/make-array-zero-by-subtracting-equal-amounts)