hdu 4292 最大流 水题

很裸的一道最大流

格式懒得排了，注意把人拆成两份，一份连接食物，一份连接饮料

4 3 3　　//4个人，3种食物，3种饮料
1 1 1　　//食物每种分别为1
1 1 1　　//饮料每种数目分别为1
YYN　　　//第一个人对第1,2,3种食物的态度为接受，接受和拒绝
NYY
YNY
YNY
YNY　　　//第一个人对第1,2,3种饮料的态度为接受，拒绝和接受
YYN
YYN
NNY

3

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
using namespace std;
const int maxn=11005;
const int MAXN = 10010;//点数的最大值
const int MAXM = 400010;//边数的最大值
const int INF = 0x3f3f3f3f;
struct Edge
{
int to,next,cap,flow;
}edge[MAXM];//注意是MAXM
int tol;
int head[MAXN];
int gap[MAXN],dep[MAXN],cur[MAXN];
void init()
{
    tol = 0;
    memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w,int rw = 0)
{
    edge[tol].to = v; edge[tol].cap = w; edge[tol].flow = 0;
    edge[tol].next = head[u]; head[u] = tol++;
    edge[tol].to = u; edge[tol].cap = rw; edge[tol].flow = 0;
    edge[tol].next = head[v]; head[v] = tol++;
}
int Q[MAXN];
void BFS(int start,int end)
{
    memset(dep,-1,sizeof(dep));
    memset(gap,0,sizeof(gap));
    gap[0] = 1;
    int front = 0, rear = 0;
    dep[end] = 0;
    Q[rear++] = end;
    while(front != rear)
    {
        int u = Q[front++];
        for(int i = head[u]; i != -1; i = edge[i].next)
        {
            int v = edge[i].to;
            if(dep[v] != -1)continue;
            Q[rear++] = v;
            dep[v] = dep[u] + 1;
            gap[dep[v]]++;
        }
    }
}
int S[MAXN];
int sap(int start,int end,int N)
{
BFS(start,end);
memcpy(cur,head,sizeof(head));
int top = 0;
int u = start;
int ans = 0;
while(dep[start] < N)
{
if(u == end)
{
int Min = INF;
int inser;
for(int i = 0;i < top;i++)
if(Min > edge[S[i]].cap - edge[S[i]].flow)
{
Min = edge[S[i]].cap - edge[S[i]].flow;
inser = i;
}
for(int i = 0;i < top;i++)
{
edge[S[i]].flow += Min;
edge[S[i]^1].flow -= Min;
}
ans += Min;
top = inser;
u = edge[S[top]^1].to;
continue;
}
bool flag = false;
int v;
for(int i = cur[u]; i != -1; i = edge[i].next)
{
v = edge[i].to;
if(edge[i].cap - edge[i].flow && dep[v]+1 == dep[u])
{
flag = true;
cur[u] = i;
break;
}
}
if(flag)
{
S[top++] = cur[u];
u = v;
continue;
}
int Min = N;
for(int i = head[u]; i != -1; i = edge[i].next)
if(edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
{
Min = dep[edge[i].to];
cur[u] = i;
}
gap[dep[u]]--;
if(!gap[dep[u]])return ans;
dep[u] = Min + 1;
gap[dep[u]]++;
if(u != start)u = edge[S[--top]^1].to;
}
return ans;
}
int g[2000][2000];
int main()
{
    int i,j,k;
    #ifndef ONLINE_JUDGE
    freopen("1.in","r",stdin);
    #endif
    int n,d,f;
    while(scanf("%d%d%d",&n,&f,&d)!=EOF)
    {
        init();
        memset(g,0,sizeof(g));
        int start=0;
        int end=f+d+2*n+1;
        for(i=1;i<=f;i++)
        {
            scanf("%d",&g[0][i]);
            addedge(0,i,g[0][i]);
        }
        for(i=f+2*n+1;i<=f+2*n+d;i++)
        {
            scanf("%d",&g[i][1]);
            addedge(i,end,g[i][1]);
        }
        for(i=1;i<=n;i++)
        {
            addedge(f+i*2-1,f+i*2,1);
        }
        char s[250];
        for(i=1;i<=n;i++)
        {
            scanf("%s",s);
            for(int j=0;j<f;j++)
            {
                if(s[j]=='Y')
                {
                    addedge(j+1,f+2*i-1,1);
                }
            }
        }
        for(i=1;i<=n;i++)
        {
            scanf("%s",s);
            for(int j=0;j<d;j++)
            {
                if(s[j]=='Y')
                {
                  addedge(f+2*i,f+2*n+j+1,1);
                }
            }
        }
        printf("%d
",sap(start,end,d+f+2*n+1));
    }
    return 0;
}