219. Contains Duplicate II

/* Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k. */ class Solution { public: bool containsNearbyDuplicate(vector<int>& nums, int k) { unordered_map<int,int> mp; for(int i=0;i<nums.size();i++) { if(mp.find(nums[i])!=mp.end()) { if(abs(i-mp[nums[i]])<=k) return true; } mp[nums[i]]=i; } return false; } };