HDU 2389 Rain on your Parade (二分图匹配(Hopcroft-Carp的算法模板))
Rain on your Parade
Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 655350/165535 K (Java/Others)Total Submission(s): 3033 Accepted Submission(s): 952
But nothing ever is perfect. One of your guests works in weather forecasting. He suddenly yells, “I know that breeze! It means its going to rain heavily in just a few minutes!” Your guests all wear their best dresses and really would not like to get wet, hence they stand terrified when hearing the bad news.
You have prepared a few umbrellas which can protect a few of your guests. The umbrellas are small, and since your guests are all slightly snobbish, no guest will share an umbrella with other guests. The umbrellas are spread across your (gigantic) garden, just like your guests. To complicate matters even more, some of your guests can’t run as fast as the others.
Can you help your guests so that as many as possible find an umbrella before it starts to pour?
Given the positions and speeds of all your guests, the positions of the umbrellas, and the time until it starts to rain, find out how many of your guests can at most reach an umbrella. Two guests do not want to share an umbrella, however.
Each test case starts with a line containing the time t in minutes until it will start to rain (1 <=t <= 5). The next line contains the number of guests m (1 <= m <= 3000), followed by m lines containing x- and y-coordinates as well as the speed si in units per minute (1 <= si <= 3000) of the guest as integers, separated by spaces. After the guests, a single line contains n (1 <= n <= 3000), the number of umbrellas, followed by n lines containing the integer coordinates of each umbrella, separated by a space.
The absolute value of all coordinates is less than 10000.
2 1 2 1 0 3 3 0 3 2 4 0 6 0 1 2 1 1 2 3 3 2 2 2 2 4 4
Scenario #1: 2 Scenario #2: 2
#include<stdio.h> #include<string.h> #include<queue> #include<math.h> using namespace std; const int N = 3005; const int INF=1<<28; int head[N],to[N*N],next1[N*N],tot; //存图 int dx[N],dy[N],dis; //左边部分距离,右边部分距离,记录右边部分没有被匹配过的点的最大距离 int machx[N],nx,machy[N]; //左边部分点匹配右边点,左边部分的点个数,右边部分点匹配左边的点 bool vist[N]; void addEdg(int u,int v){ to[tot]=v; next1[tot]=head[u]; head[u]=tot++; } bool searchpath(){//找有没有增广路 queue<int>q; dis=INF; memset(dx,-1,sizeof(dx)); memset(dy,-1,sizeof(dy)); for(int i=1; i<=nx; i++) if(machx[i]==-1) q.push(i),dx[i]=0; while(!q.empty()){ int u=q.front(); q.pop(); if(dx[u]>dis) break; for(int i=head[u]; i!=-1; i=next1[i]){ int v=to[i]; if(dy[v]==-1){ dy[v]=dx[u]+1; if(machy[v]==-1) dis=dy[v]; else{ dx[machy[v]]=dy[v]+1; q.push(machy[v]); } } } } return dis!=INF; } bool findroad(int u){ for(int i=head[u]; i!=-1; i=next1[i]){ int v=to[i]; if(!vist[v]&&dy[v]==dx[u]+1){ vist[v]=1; if(machy[v]!=-1&&dy[v]==dis) continue; if(machy[v]==-1||findroad(machy[v])){ machy[v]=u; machx[u]=v; return true; } } } return false; } int MaxMatch(){ int ans=0; memset(machx,-1,sizeof(machx)); memset(machy,-1,sizeof(machy)); while( searchpath() ){ memset(vist,0,sizeof(vist)); for(int i=1; i<=nx; i++) if(machx[i]==-1) ans+=findroad(i); } return ans; } //-------------上面部分的代码为模板--------------------- struct node{ int x,y; double dis; }man[N],umb[N]; double countDis(int u,int v){ return sqrt((man[u].x-umb[v].x)*(man[u].x-umb[v].x)*1.0+(man[u].y-umb[v].y)*(man[u].y-umb[v].y)*1.0); } int main(){ int T,ny,tim,c=0; scanf("%d",&T); while(T--){ scanf("%d%d",&tim,&nx); for(int i=1;i<=nx;i++){ scanf("%d%d%lf",&man[i].x,&man[i].y,&man[i].dis); man[i].dis*=tim; } scanf("%d",&ny); for(int i=1;i<=ny;i++) scanf("%d%d",&umb[i].x,&umb[i].y); //---------------------建图--------------------- tot=0; memset(head,-1,sizeof(head)); for(int u=1;u<=nx;u++) for(int v=1;v<=ny;v++) if(man[u].dis>=countDis(u,v)) addEdg(u,v); //---------------------------------------------- int ans=MaxMatch(); printf("Scenario #%d:\n%d\n\n",++c,ans); } return 0; }
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。