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;
}