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;
}