hdu 2389

来源：互联网发布：网络维护主要做什么编辑：程序博客网时间：2024/05/17 12:03

这题明显的二分匹配第一次用匈牙利算法居然TLE。。。。

然后改用HK A了 156ms~

图用的邻接表存的，没用vector，可能快点吧。。

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <queue>

using namespace std;

int n,m,head[3001],speed[3001],next[9000001],e[9000001],matchx[3001],matchy[3001],dx[3001],dy[3001];
struct point{
int x,y;
} man[3001],unbrella[3001];

bool bfs(){
memset(dx,0,sizeof(int)*(m+1));
memset(dy,0,sizeof(int)*(n+1));
bool find = false;
queue<int> q;
for(int i = 1;i<=m;i++) if(matchx[i]==-1) q.push(i);
while(!q.empty()){
int x = q.front();q.pop();
for(int i = head[x];i!=-1;i = next[i]){
int y = e[i];
if(!dy[y]){
dy[y] = dx[x]+1;
if(matchy[y]==-1) find = true;
else{
dx[matchy[y]] = dy[y] + 1;
q.push(matchy[y]);
}
}
}
}
return find;
}

bool find(int u){
for(int i = head[u];i!=-1;i = next[i]){
int v = e[i];
if(dy[v]==dx[u]+1){
dy[v] = 0;
if(matchy[v]==-1||find(matchy[v])){
matchy[v] = u;
matchx[u] = v;
return true;
}
}
}
return false;
}

int HK(){
memset(matchx,-1,sizeof(int)*(m+1));
memset(matchy,-1,sizeof(int)*(n+1));
int ans = 0;
while(bfs()){
for(int i = 1;i<=m;i++){
if(matchx[i]==-1&&find(i)) ans++;
}
}
return ans;
}

inline int d(int i,int j){
point &mm = man[i];
point &un = unbrella[j];
return (mm.x-un.x)*(mm.x-un.x)+(mm.y-un.y)*(mm.y-un.y);
}

inline void addEdge(int &count,int u,int v){
e[count] = v;
int temp = head[u];
head[u] = count;
next[count++] = temp;
}

int main(void){
//freopen("D:\\data.txt","r",stdin);
int ca;
scanf("%d",&ca);
for(int tt = 1;tt<=ca;tt++){
int t;
scanf("%d",&t);
scanf("%d",&m);
memset(head,-1,sizeof(int)*(m+1));
int count=0;
for(int i = 0;i<m;i++)
scanf("%d %d %d",&man[i].x,&man[i].y,&speed[i]);
scanf("%d",&n);
for(int i = 0;i<n;i++)
scanf("%d %d",&unbrella[i].x,&unbrella[i].y);
for(int i = 0;i<m;i++){
for(int j = 0;j<n;j++){
int dis = d(i,j);
if(dis<=t*t*speed[i]*speed[i])
addEdge(count,i+1,j+1);
}
}
int ans = HK();
printf("Scenario #%d:\n%d\n\n",tt,ans);
}
}