这是我写的，不知道哪有错误，运行的时候好像是个死循环
#include <math.h>
#include <stdio.h>
main()
{
    int time=0,k;
    double p,q;
    struct river
    {int m;
    int w;
    };
    struct river side;
    struct river1
    {int a;
    int b;
    };
    struct river1 boat;
    side.m=3;
    side.w=3;
    boat.a=1;
    boat.b=1;
    k=1;
    while(side.m!=0&&side.w!=0)
    {
        p=pow(-1,k)*boat.a+side.m;
        q=pow(-1,k)*boat.b+side.w;
        if(p>=q)
        {
            side.m=p;
            side.w=q;
            printf("  %d",k);
            k++;
        }
        else
        {
            if(time<3)
            {
                boat.a=time;
                boat.b=2-time;
                time++;
            }
            else time=0;
        }
    }
    getch();
}