7-46 爬动的蠕虫 (15 分) C语言答案

#include "stdio.h"
int main(void)
{
    int N,U,D;
    scanf("%d%d%d",&N,&U,&D);
    int len=0,time=0;
    while (1)
    {
        if(len>=N)
        {
            printf("%d",time);
            return 0;
        }
        if(time%2==0)
        {
            len+=U;
        } else
        {
            len-=D;
        }
        time++;
    }
}