算法篇——Cantor的数表 - SteveWang - 博客园 (cnblogs.com)

#include <bits/stdc++.h>
using namespace std;
int high(int n)
{return n*(n+1)/2;
}
int main()
{int k;cin>>k;int n=1;while(1){if(high(n)>=k){break;}n++;}  int m=high(n);int w=m-k+1;if(n%2==0){cout<<n-w+1<<"/"<<w;}else{ cout<<w<<"/"<<n-w+1;}return 0;
}