<p>Given an integer array <code>nums</code> and an integer <code>k</code>, return <code>true</code> <em>if there are two <strong>distinct indices</strong> </em><code>i</code><em> and </em><code>j</code><em> in the array such that </em><code>nums[i] == nums[j]</code><em> and </em><code>abs(i - j) &lt;= k</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,1], k = 3
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,0,1,1], k = 1
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,3,1,2,3], k = 2
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>9</sup> &lt;= nums[i] &lt;= 10<sup>9</sup></code></li>
	<li><code>0 &lt;= k &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:

    static bool compare(pair<int, int> a, pair<int, int>b){
        return a.first < b.first;
    }

    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        vector<pair<int, int>>pairs;
        for(int i = 0; i < nums.size(); i++){
            pairs.push_back(make_pair(nums[i], i));
        }
        sort(pairs.begin(), pairs.end(), compare);

        int start = 0;
        int end = 1;
        while(end < pairs.size()){
            if(pairs[end].first == pairs[start].first){
                if(end > start && ((pairs[end].second - pairs[start].second) <= k)){
                    return true;
                }
                start++;
                end++;
            } else{
                // start = end;
                start++;
                end++;
                // return (pairs[end].second - pairs[start].second) > k ? true : false;
            }
        }

        // if(end-1 > start && (pairs[end-1].second - pairs[start].second <= k)){
        //             return true;
        // }

        return false;
    }
};
70581