HackerRank Pairs

5 2
1 5 3 4 2

int pairs(int k, vector<int> arr) {
    int result = 0;
    sort(arr.begin(), arr.end());
    for(int i = 0 ; i<arr.size() ; i++){
        int left = i, right = arr.size() - 1;
        while(left<=right){
            int mid = (left + right) / 2;
            int now = arr[mid];
            if(now - arr[i] == k){
                result++;
                break;
            }
            else if(now - arr[i] > k) right = mid - 1;
            else left = mid + 1;
        }
    }
    return result;
}