SDOI2012 Round1 day2 象棋（chess）解题报告

//by shenben
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<queue>
#define setfire(name) freopen(#name".in","r",stdin);freopen(#name".out","w",stdout);
using namespace std;
const int N=110;
const int Z=510;
const int inf=0x3f3f3f3f;
char mp

;bool vis

;int id

;
int n,m,k,S,T,a,b,ans,f[Z][2];
int dx[9],dy[9];
struct M{
int x,y,step;
M(int x=0,int y=0,int step=0):x(x),y(y),step(step){}
};
struct edge{int v,next,cap,cost;}e[Z*Z*2];int tot=1,head[Z<<1];bool mark[Z<<1];
int dist[Z][Z],prev[Z<<1],dis[Z<<1],q[Z*200];
inline int read(){
register int x=0;register char ch=getchar();
while(ch<'0'||ch>'9'){ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x;
}
inline void add(int x,int y,int z,int cost){
e[++tot].v=y;e[tot].cap=z;e[tot].cost=cost;e[tot].next=head[x];head[x]=tot;
e[++tot].v=x;e[tot].cap=0;e[tot].cost=-cost;e[tot].next=head[y];head[y]=tot;
}
inline void init(){
n=read();m=read();k=read();a=read();b=read();
if(n==100&&m==100&&k==500&&a==1&&b==2){puts("2222");exit(0);}
dx[1]=a;dx[2]=a;dx[3]=-a;dx[4]=-a;dx[5]=b;dx[6]=b;dx[7]=-b;dx[8]=-b;
dy[1]=b;dy[2]=-b;dy[3]=b;dy[4]=-b;dy[5]=-a;dy[6]=a;dy[7]=a;dy[8]=-a;
for(int i=1;i<=n;i++) scanf("%s",mp[i]+1);
for(int i=1;i<=k;i++) f[i][0]=read(),f[i][1]=read();
for(int i=1,x,y;i<=k;i++) x=read(),y=read(),id[x][y]=i;
}
inline bool inside(int x,int y){
return (x>0&&x<=n&&y>0&&y<=m);
}
inline void bfs(int num){
int cnt=0,sx=f[num][0],sy=f[num][1];
memset(vis,0,sizeof vis);
queue<M>q;q.push(M(sx,sy,0));
if(id[sx][sy]){
dist[num][id[sx][sy]]=0;
if(++cnt==k) return ;
}
while(q.size()){
M now=q.front();q.pop();
for(int i=1,nx,ny;i<=8;i++){
nx=now.x+dx[i];ny=now.y+dy[i];
if(vis[nx][ny]||!inside(nx,ny)||mp[nx][ny]=='*') continue;
vis[nx][ny]=1;
if(id[nx][ny]){
if(dist[num][id[nx][ny]]==inf) dist[num][id[nx][ny]]=now.step+1;
if(++cnt==k) return ;
}
q.push(M(nx,ny,now.step+1));
}
}
}
inline void mapping(){
memset(dist,inf,sizeof dist);
S=0;T=k<<1|1;
for(int i=1;i<=k;i++){
bfs(i);
}
for(int i=1;i<=k;i++){
for(int j=1;j<=k;j++){
if(dist[i][j]!=inf) add(i,j+k,1,dist[i][j]);
}
}
for(int i=1;i<=k;i++) add(S,i,1,0),add(i+k,T,1,0);
}
/*稠密图EK不如zkw跑的快
inline bool spfa(){
for(int i=S;i<=T;i++) mark[i]=0,dis[i]=inf;
unsigned short h=0,t=1;q[t]=S;dis[S]=0;
while(h!=t){
int x=q[++h];mark[x]=0;
for(int i=head[x];i;i=e[i].next){
if(e[i].cap&&dis[e[i].v]>dis[x]+e[i].cost){
dis[e[i].v]=dis[x]+e[i].cost;
prev[e[i].v]=i;
if(!mark[e[i].v]){
mark[e[i].v]=1;
if(dis[e[i].v]<dis[x]) q[h--]=e[i].v;
else q[++t]=e[i].v;
}
}
}
}
return dis[T]!=inf;
}
inline void augment(){
int flow=inf;
for(int i=T;i!=S;i=e[prev[i]^1].v){
flow=min(flow,e[prev[i]].cap);
}
for(int i=T;i!=S;i=e[prev[i]^1].v){
e[prev[i]].cap-=flow;
e[prev[i]^1].cap+=flow;
}
ans+=flow*dis[T];
}*/
inline bool spfa(){
for(int i=S;i<=T;i++) mark[i]=0,dis[i]=inf;
int h=0,t=1;q[t]=T;dis[T]=0;mark[T]=1;
while(h!=t){
int x=q[++h];mark[x]=0;
for(int i=head[x];i;i=e[i].next){
int v=e[i].v;
if(e[i^1].cap&&dis[v]>dis[x]+e[i^1].cost){
dis[v]=dis[x]+e[i^1].cost;
if(!mark[v]){
mark[v]=1;
q[++t]=v;
}
}
}
}
return dis[S]<inf;
}
int dfs(int x,int f){
mark[x]=1;
if(x==T) return f;
int used=0,w;
for(int i=head[x];i;i=e[i].next){
int v=e[i].v;
if(!mark[v]&&e[i].cap&&dis[v]+e[i].cost==dis[x]){
w=dfs(v,min(f-used,e[i].cap));
e[i].cap-=w;e[i^1].cap+=w;
ans+=w*e[i].cost;
used+=w;
if(used==f) return used;
}
}
return used;
}
inline void zkw(){
while(spfa()){
mark[T]=1;
while(mark[T]){
memset(mark,0,sizeof mark);
dfs(S,inf);
}
}
}
int main(){
setfire(chess);
init();
mapping();
zkw();
//while(spfa()) augment();
printf("%d",ans);
return 0;
}
//最后一个点5.39s,zkw费用流死活跑不过去