Problem

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.

Example

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

Input: nums = [1,0,1,1], k = 1
Output: true

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

Code

static int var = [](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        int size = nums.size();
        if(size<=1)
            return 0;
        map<int,int> dict;
        for(int i = 0;i < size;i++)
        {
            if(dict.find(nums[i])!=dict.end()){
                if(i - dict[nums[i]] <= k)
                    return true;
                else
                    dict[nums[i]] = i;
            }
            else{
                dict[nums[i]] = i;
            }
            
        }
        return false;
    }
};

Result

219. Contains Duplicate II.png