Leecode 18. 四数之和

classSolution{public:vector<vector<int>>fourSum(vector<int>&nums,inttarget){vector<vector<int>>result;sort(nums.begin(),nums.end());for(inti=0;i<nums.size();i++){//去重if(i>0&&nums[i]==nums[i-1])continue;for(intj=i+1;j<nums.size();j++){//去重if(j>i+1&&nums[j]==nums[j-1])continue;intleft=j+1;intright=nums.size()-1;while(right>left){if((long)nums[i]+nums[j]+nums[left]+nums[right]>target)right--;elseif((long)nums[i]+nums[j]+nums[left]+nums[right]<target)left++;else{result.push_back(vector<int>{nums[i],nums[j],nums[left],nums[right]});//去重while(right>left&&nums[right]==nums[right-1])right--;while(right>left&&nums[left]==nums[left+1])left++;right--;left++;}}}}returnresult;}};