Gopher II (Hungarian algorithm template)

Describe

The Gopher family, having averted of the canine threat, must face a new predator.

The is N gophers and M gopher holes, each at distinct (x, y) coordinates. A hawk arrives and if a gopher does not reach a hole in s seconds it's vulnerable to being eaten. A hole can save at the most one gopher. All the Gophers run at the same velocity v. The Gopher family needs an escape strategy that minimizes the number of vulnerable Gophers.

Input

The input contains several cases. The first line of all case contains four positive integers less than 100:n, M, S, and V. The next n lines give the coordinates of the Gophers; The following m lines give the coordinates of the gopher holes. All distances is in metres; All times is in seconds; All velocities is in metres per second.

Output

Output consists of a, giving the number of vulnerable Gophers.

Sample input

2 2 5 10
1.0 1.0
2.0 2.0
100.0 100.0
20.0 20.0

Sample output

1

The eagle catches the mouse, n mouse, M hole, each hole can hold only one mouse, speed is V, safe distance is s*v, asks to be eaten the mouse, uses the Hungarian algorithm

1#include <iostream>2#include <cstring>3#include <cstdio>4#include <cmath>5 using namespacestd;6 7 intn,m,s,v;8 structDis9 {Ten     Doublex, y; One}gop[ the],hol[ the];//the position of the mouse, the hole A intflag[ the],par[ the];//whether the hole matches, the hole matches the mouse -  - intMatchintu) the { -     DoubleLen; -      for(intI=1; i<=m;i++){ -Len=sqrt ((gop[u].x-hol[i].x) * (gop[u].x-hol[i].x) + (GOP[U].Y-HOL[I].Y) * (gop[u].y-hol[i].y)); +         if(len-s*v*1.0<1e-6&&!flag[i]) {//can reach the forward hole in the eagle and does not match in this match -flag[i]=1;//Match +             if(!par[i]| | Match (Par[i])) {//the hole has no mice or can safely transfer the hole's mouse to another hole. APar[i]=u;//into the hole at                 return 1; -             } -         } -     } -     return 0; - } in  - intMain () to { +      while(SCANF ("%d%d%d%d", &n,&m,&s,&v)! =EOF) { -          for(intI=1; i<=n;i++){ thescanf"%LF%LF",&gop[i].x,&gop[i].y); *         } $          for(intI=1; i<=m;i++){Panax Notoginsengscanf"%LF%LF",&hol[i].x,&hol[i].y); -         } the         intsum=0; +memset (PAR,0,sizeof(PAR)); A          for(intI=1; i<=n;i++){ thememset (Flag,0,sizeof(flag));//Initialize each time +sum+=match (i); -         } $printf"%d\n", N-sum); $     } -     return 0; -}

Gopher II (Hungarian algorithm template)