Problem
http://e-tutor.itsa.org.tw/e-Tutor/mod/programming/view.php?id=2969
Thinking
TODO
Solution
#include <iostream>
#include <set>
using namespace std;
int main(){
int num;
while(cin >> num){
set<int> S;
S.insert(1);
for(int T = 2 ; S.size() != num ;T++ ){
set<int>::iterator search = S.find(T);
if(search == S.end()){
S.insert(*S.rbegin() + T);
}
}
cout << *S.rbegin() << endl;
}
}
