题解 | #牛牛的三元组问题#

class Solution {
public:
    vector<vector<int> > findTriplets(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int n = nums.size();
        vector<vector<int>> ret;
        for (int i=0; i<n-2; i++) {
            if (i>0 && nums[i]==nums[i-1]) continue;
            int l = i+1;
            int r = n-1;
            while (l < r) {
                int sum = nums[i] + nums[l] + nums[r];
                if (sum == 0) {
                    ret.push_back({nums[i], nums[l], nums[r]});
                    l++; r--;
                    while (l<n-1 && nums[l+1]==nums[l])
                        l++;
                    while (r>i+1 && nums[r-1]==nums[r])
                        r--;  
                } else if (sum > 0) {
                    r--;
                } else {
                    l++;
                }
            }
        }
        return ret;
    }
};