leetcode 3sum

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        vector<vector<int>> res
        if(nums.size() < 3) return res
        sort(nums.begin(), nums())
        const int target = 0
        auto last = nums()
        for(auto i = nums.begin(); i < last - 2; ++i) {
            if(i > nums.begin() && *i == *(i - 1)) continue
            auto j = i + 1
            auto k = last - 1
            while(j < k) {
                if(*i + *j + *k < target) {
                    ++j;
                    while(*j == *(j-1) && j < k) ++j;
                }else if(*i + *j + *k > target) {
                    --k
                    while(*k == *(k+1) && j < k) --k
                }else {
                    res.push_back({*i, *j, *k});
                    ++j;
                    --k;
                    while(*j == *(j-1) && j < k) ++j;
                    while(*k == *(k+1) && j < k) --k;
                }
            }
        }
        return res;
    }
};