kSumPairs.cpp

class Solution {
public:
    int maxOperations(vector<int>& nums, int k) {
        sort(nums.begin(), nums.end());
        int start = 0, end = nums.size() - 1;
        int count = 0;
        while (start < end) {
            if (nums[start] + nums[end] == k){
                count++;
                start++;
                end--;
            }
            else if (nums[start] + nums[end] > k) {
                end--;
            }
            else {
                start++;
            }
        }
        return count;
    }
};