Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.
Note: The solution set must not contain duplicate triplets.
For example, given array S = [-1, 0, 1, 2, -1, -4], A solution set is: [ [-1, 0, 1], [-1, -1, 2] ]
solution :
class Solution {
public:
vector<vector<int>> threeSum(vector<int>& nums) {
int len=nums.size();
vector<vector<int>> solution;//(m);
std::sort(nums.begin(),nums.end());
for(int i=0;i<len;i++){
int sum=-nums[i];
int left=i+1;
int right=len-1;
while(left<right){
int number=nums[left]+nums[right];
if(sum>number){
left++;
}else if(sum<number){
right--;
}else{
vector<int> tmp(3,0);
tmp[0]=nums[i];
tmp[1]=nums[left];
tmp[2]=nums[right];
solution.push_back(tmp);
while(left<right && nums[left]==tmp[1]) left++;
while(left<right && nums[right]==tmp[2]) right--;
}
}
while(i+1<len && nums[i]==nums[i+1]) i++;
}
return solution;
}
};