http://acm.hit.edu.cn/hoj/problem/view?id=1649
前15个数为
1/1 1/2 2/1 3/1 2/2 1/3 1/4 2/3 3/2 4/1 5/1 4/2 3/3 2/4 1/5
从对角线上数
奇数对角线从下往上 偶数对角线从上往下
#include <stdio.h>
#include <math.h>
int main()
{
int n, k;
int i, j;
while (scanf("%d", &n) != EOF)
{
for(k = ceil(sqrt(n)); 0.5 * k *(k + 1) < n; k++) {}
for(i = 1,j = k; (i < k) && (j > 1); i++, j--)
{
if(i == (0.5 * k * (k + 1) - n + 1) )
break;
}
if(k %2 != 0)
printf("TERM %d IS %d/%d\n", n, i, j);
else
printf("TERM %d IS %d/%d\n", n, j, i);
}
return 0;
}