CodeForces 590B Chip 'n Dale Rescue Rangers

CodeForces 590B Chip 'n Dale Rescue Rangers

这题可以o(1)推出公式，也可以二分答案+验证。

#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<cstdio>
using namespace std;double X1,X2,Y1,Y2;
double v,t;
double vx,vy,wx,wy;bool check(double mid)
{double tmpx,tmpy;if(mid<=t){tmpx=X1+mid*vx;tmpy=Y1+mid*vy;double dis=sqrt((X2-tmpx)*(X2-tmpx)+(Y2-tmpy)*(Y2-tmpy));if(dis/v>mid) return 0;return 1;}else{tmpx=X1+t*vx;tmpy=Y1+t*vy;tmpx=tmpx+(mid-t)*wx;tmpy=tmpy+(mid-t)*wy;double dis=sqrt((X2-tmpx)*(X2-tmpx)+(Y2-tmpy)*(Y2-tmpy));if(dis/v>mid) return 0;return 1;}
}int main()
{scanf("%lf%lf%lf%lf",&X1,&Y1,&X2,&Y2);scanf("%lf%lf",&v,&t);scanf("%lf%lf%lf%lf",&vx,&vy,&wx,&wy);double l=0,r=9999999999;double ans;int t=200;while(t--){double mid=(l+r)/2.0;if(check(mid)){ans=mid;r=mid;}else l=mid;}printf("%.18lfn",ans);return 0;
}

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