[LeetCode][JavaScript]Contains Duplicate II

Contains Duplicate II

Given an array of integers and an integer k, return true if and only if there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k.

https://leetcode.com/problems/contains-duplicate-ii/

数组中两个相同值的数，下标之差要小于等于k。

/**
* @param {number[]} nums
* @param {number} k
* @return {boolean}
*/
var containsNearbyDuplicate = function(nums, k) {
var map = {};
for(var i in nums){
if(map[nums[i]]){
if(Math.abs(map[nums[i]] - i) <= k){
return true;
}
}
map[nums[i]] = i;
}
return false;
};