1193 : 분수 찾기 [C++]

#include <iostream>
#include <vector>

using namespace std;

int main()
{
 vector<int> Sum;
 Sum.push_back(0);

 for (int i = 1; Sum[i - 1] < 10000000; i++)
  Sum.push_back(Sum[i - 1] + i);

 int X;
 cin >> X;

 int Start = 0;

 for (int i = 1; Sum[i - 1] < 10000000; i++)
 {
  if (Sum[i - 1] < X && X <= Sum[i])
  {
   X -= Sum[i - 1] + 1;
   Start = i;
   break;
  }
 }

 if (Start % 2 == 1)
 {
  cout << Start - X << "/" << 1 + X  ;
 }
 else
 {
  cout << 1 + X << "/" << Start - X;
 }
}