【Luogu】P2445动物园（最大流）

　　题目链接

　　题目本身还是比较水的吧……容易发现是最大流套上dinic跑一遍就好了，并不会超时。

　　比较不偷税的一点是关于某动物的所有目击报告都符合才能连边……qwqqwqqwq

　　

#include<cstdio>
#include<algorithm>
#include<cctype>
#include<cstring>
#include<cstdlib>
#include<queue>
#define maxn 1000
using namespace std;
inline long long read(){
    long long num=0,f=1;
    char ch=getchar();
    while(!isdigit(ch)){
        if(ch=='-')    f=-1;
        ch=getchar();
    }
    while(isdigit(ch)){
        num=num*10+ch-'0';
        ch=getchar();
    }
    return num*f;
}

int u[5]={0,0,1,0,-1};
int w[5]={0,1,0,-1,0};

struct Edge{
    int next,to,val;
}edge[maxn*2];
int head[maxn],num;
inline void addedge(int from,int to,int val){
    edge[++num]=(Edge){head[from],to,val};
    head[from]=num;
}
inline void add(int from,int to,int val){
    addedge(from,to,val);
    addedge(to,from,0);
}

inline int count(int i){    return i&1?i+1:i-1;    }

int pre[maxn];
int Start,End;
bool vis[maxn];
int dfn[maxn];
int list[maxn];

bool bfs(){
    memset(vis,0,sizeof(vis));    dfn[Start]=1;    vis[Start]=1;
    queue<int>q;    q.push(Start);
    while(!q.empty()){
        int from=q.front();    q.pop();
        for(int i=head[from];i;i=edge[i].next){
            int to=edge[i].to;
            if(vis[to]||edge[i].val<=0)    continue;
            vis[to]=1;    dfn[to]=dfn[from]+1;
            q.push(to);
        }
    }
    return vis[End];
}

int dfs(int x,int val){
    if(val==0||x==End)    return val;
    vis[x]=1;    int flow=0;
    for(int &i=list[x];i;i=edge[i].next){
        int to=edge[i].to;
        if(vis[to]||dfn[to]!=dfn[x]+1||edge[i].val<=0)    continue;
        int now=dfs(to,min(val,edge[i].val));
        if(x!=End)    pre[to]=x;    edge[i].val-=now;    edge[count(i)].val+=now;    val-=now;    flow+=now;
        if(val<=0)    break;
    }
    if(val!=flow)    dfn[x]=-1;
    return flow;
}

inline int maxflow(){
    int ans=0;
    while(bfs()){
        memset(vis,0,sizeof(vis));
        for(int i=Start;i<=End;++i)    list[i]=head[i];
        int now=dfs(Start,0x7fffffff);
        if(now==0)    break;
        ans+=now;
    }
    return ans;
}

int s[maxn][maxn];
char c[maxn];
bool ext[maxn][maxn];
int dis[105][105][105];
int v[maxn];
bool exa[maxn];
int f[maxn][maxn];
int sum[maxn];

struct Node{
    int x,y;
}que[maxn];

int main(){
    memset(dis,127/3,sizeof(dis));    int inf=dis[0][0][0];
    int n=read();
    for(int i=1;i<=n;++i){
        scanf("%s",c+1);
        for(int j=1;j<=n;++j)
            if(c[j]=='*')    s[i][j]=1;
            else             s[i][j]=0;
    }
    int p=read();    End=p*2+1;
    for(int i=1;i<=p;++i)    que[i]=(Node){read(),read()};
    for(int i=1;i<=p;++i){
        add(Start,i,1);    add(i+p,End,1);
        queue<Node>q;    q.push(que[i]);    dis[i][que[i].x][que[i].y]=0;
        while(!q.empty()){
            Node from=q.front();    q.pop();
            //printf("%d %d %d<<<<<<<<
",i,from.x,from.y);
            for(int j=1;j<5;++j){
                int nx=from.x+u[j];
                int ny=from.y+w[j];
                //printf("%d %d %d %d><>
",nx,ny,s[nx][ny],dis[i][from.x][from.y]);
                if(nx<1||nx>n||ny<1||ny>n||s[nx][ny]||dis[i][nx][ny]!=inf)    continue;
                dis[i][nx][ny]=dis[i][from.x][from.y]+1;
                q.push((Node){nx,ny});
            }
        }
    }
    for(int i=1;i<=p;++i)    v[i]=read();
    int r=read();
    for(int i=1;i<=r;++i){
        int t=read(),x=read(),y=read(),d=read();    sum[d]++;
        for(int j=1;j<=p;++j){
            //printf("%d %d>>>
",j,dis[j][x][y]);
            int ret=v[d]*t;
            if(ret>=dis[j][x][y])    f[j][d]++;
        }
    }
    for(int i=1;i<=p;++i)
        for(int j=1;j<=p;++j)
            if(sum[i]==f[j][i])    add(j,i+p,1);
    maxflow();
    for(int i=1+p;i<End;++i){
        for(int j=head[i];j;j=edge[j].next){
            int to=edge[j].to;
            if(to==End||edge[j].val==0)    continue;
            printf("%d %d %d
",i-p,que[to].x,que[to].y);
            break;
        }
    }
    return 0;
}