HDU 4292 Food(dinic +拆点)

题目链接

我做的伤心了，不知是模版效率低，还是错了，交上就是TLE，找了份别人的代码，改了好几下终于过了。。

#include <cstdio>
#include <cstring>
#include <queue>
#include <map>
#include <iostream>
using namespace std;
#define INF 0x3fffffff
char food[201][201],drink[201][201];
struct node
{
    int u,v,next,re,w;
}edge[200001];
int first[2001],dis[2001];
int t,str,end;
void CL()
{
    t = 1;
    memset(first,-1,sizeof(first));
}
void add(int u,int v,int w)
{
    edge[t].u = u;
    edge[t].v = v;
    edge[t].w = w;
    edge[t].re = t+1;
    edge[t].next = first[u];
    first[u] = t++;
    edge[t].u = v;
    edge[t].v = u;
    edge[t].w = 0;
    edge[t].re = t-1;
    edge[t].next = first[v];
    first[v] = t ++;
}
int bfs()
{
    int u,v,i;
    memset(dis,0xff,sizeof(dis));
    queue<int> que;
    que.push(str);
    dis[str] = 0;
    while(!que.empty())
    {
        u = que.front();
        que.pop();
        for(i = first[u];i != -1;i = edge[i].next)
        {
            v = edge[i].v;
            if(edge[i].w > 0&&dis[v] < 0)
            {
                dis[v] = dis[u] + 1;
                que.push(v);
            }
        }
    }
    if(dis[end] > 0) return 1;
    else return 0;
}
int dfs(int u,int step)
{
    int i,temp,v,tf = 0;
    if(u == end) return step;
    for(i = first[u];i != -1;i = edge[i].next)
    {
        v = edge[i].v;
        if(edge[i].w > 0&&dis[v] == dis[u] + 1&&(temp = dfs(v,min(step,edge[i].w))))
        {
            edge[i].w -= temp;
            edge[edge[i].re].w += temp;
            return temp;
        }
    }
    if(!tf) dis[u] = -1;//注意这里
    return tf;
}
int main()
{
    int i,j,res,ans,n,f,d,temp;
    while(scanf("%d%d%d",&n,&f,&d)!=EOF)
    {
        ans = 0;
        str = 0;
        end = 2000;
        CL();
        for(i = 1; i <= f;i ++)
        {
            scanf("%d",&temp);
            add(str,i,temp);
        }
        for(i = 1;i <= d;i ++)
        {
            scanf("%d",&temp);
            add(f+i,end,temp);
        }
        for(i = 1;i <= n;i ++)
        add(f+d+i,f+d+n+i,1);
        for(i = 0;i < n;i ++)
        {
            scanf("%s",food[i]);
        }
        for(i = 0;i < n;i ++)
        {
            scanf("%s",drink[i]);
        }
        for(i = 0;i < n;i ++)
        {
            for(j = 0;j < f;j ++)
            {
                if(food[i][j] == 'Y')
                add(j+1,f+d+i+1,1);
            }
        }
        for(i = 0;i < n;i ++)
        {
            for(j = 0;j < d;j ++)
            {
                if(drink[i][j] == 'Y')
                add(f+d+n+i+1,f+j+1,1);
            }
        }
        while(bfs())//注意这部分
        {
           while(res = dfs(str,INF))
           ans+= res ;
        }
        printf("%d\n",ans);
    }
    return 0;
}