[LeetCode]3sum

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
class solution{
public:
vector<vector<int> > threesum(vector<int>& num){
vector<vector<int> > result;
if(num.size()<3) return result;
sort(num.begin(),num.end());
const int target=0;

auto last=num.end();
for(auto a=num.begin();a<prev(last,2);
a=upper_bound(a,prev(last,2),*a)){
for(auto b=next(a);b<prev(last);
b=upper_bound(b,prev(last),*b)){
const int c=target-*a-*b;
if(binary_search(next(b),last,c))
{
vector<int> coll;
coll.push_back(*a);
coll.push_back(*b);
coll.push_back(c);
result.push_back(coll);
}

}
}
return result;
}
};
void print(vector< vector<int> > & result)
{

for(int i = 0; i < result.size(); i++)
{
for(int j = 0; j < result[i].size(); j++)
{
cout<<result[i][j]<<" ";
}
cout<<endl;
}

}
int main()
{
vector<int> a;
a.push_back(-1);
a.push_back(0);
a.push_back(1);
a.push_back(2);
a.push_back(-1);
a.push_back(4);
solution s;
s.threesum(a);
print(s.threesum(a));
}