{

typedef long long ll;

vector<vector<int>> fourSum(vector<int>& nums, int target) {

if(nums.size()<=3) return {};

sort(nums.begin(),nums.end());

int n=nums.size();

vector<vector<int>>ans;

for(int i=0;i<n-3;i++){

if(i>0 && nums[i]==nums[i-1]) continue;

for(int j=i+1;j<n-2;j++){

if(j>1 && nums[j]==nums[j-1] && i!=j-1) continue;

int k=j+1,l=n-1;

ll sum=nums[i]+nums[j];

while(l>k){

if(nums[k]+nums[l]+sum==target){

cout<<i<<" "<<j<<" "<<k<<" "<<l<<endl;

ans.push_back({nums[i],nums[j],nums[k],nums[l]});

while(l>k && nums[l]==nums[l-1]) l--;

while(l>k && nums[k]==nums[k+1]) k++;

l--,k++;

}

else if(nums[l]+nums[k]+sum>target) l--;

else k++;

}

}

}

return ans;

}