CSU 1650 影魔大战

简单题。

首先判断两个圆是否都与坐标轴相交，有一个不相交直接输出NO

剩下的情况都是相交的。让算一算四个交点。最后只有四种情况了。

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

using namespace std;



int main()

{

    double Vx, x, y, T1, R1, T2, R2;

    while (~scanf("%lf%lf%lf", &Vx, &x, &y))

    {

        scanf("%lf%lf%lf%lf", &T1, &R1, &T2, &R2);



        double TT1, TT2, RR1, RR2;

        if (R1 > R2)RR1 = R1, RR2 = R2, TT1 = T1, TT2 = T2;    

        else RR1 = R2, RR2 = R1, TT1 = T2, TT2 = T1;

        if (fabs(y)>R1 || fabs(y)>R2)

        {

            printf("No\n");

            continue;

        }

        double A, B, C, D;

        A = x - sqrt(RR1*RR1 - y*y);

        B = x + sqrt(RR1*RR1 - y*y);

        C = x - sqrt(RR2*RR2 - y*y);

        D = x + sqrt(RR2*RR2 - y*y);



        if (A>0 && A / Vx >= TT1 && (C - A) / Vx >= TT2) printf("Yes\n");

        else if (A>0 && A / Vx >= TT1 && (D - A) / Vx >= TT2) printf("Yes\n");

        else if (C>0 && C / Vx >= TT2 && (B - C) / Vx >= TT1) printf("Yes\n");

        else if (D>0 && D / Vx >= TT2 && (B - D) / Vx >= TT1) printf("Yes\n");

        else printf("No\n");

    }

    return 0;

}