题解 | #牛牛的三元组问题#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型vector 
     * @return int整型vector<vector<>>
     */
    vector<vector<int> > result;
    vector<int> path;
    int pathSum = 0;
    void backTrack(vector<int>& nums, int start, int end){
        if(path.size() == 3 && pathSum == 0){
            result.push_back(path);
            return;
        }
        for(int i = start; i < end; i++){
            if(i > start && nums[i] == nums[i-1]) continue;
            pathSum += nums[i];
            path.push_back(nums[i]);
            backTrack(nums, i + 1, end);
            pathSum -= path.back();
            path.pop_back();  
        }
    }
    vector<vector<int> > findTriplets(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        backTrack(nums, 0, nums.size());
        return result;
    }
};