Food
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3658 Accepted Submission(s): 1246
Problem Description
You, a part-time dining service worker in your college’s dining hall, are now confused with a new problem: serve as many people as possible.
The issue comes up as people in your college are more and more difficult to serve with meal: They eat only some certain kinds of food and drink, and with requirement unsatisfied, go away directly.
You have prepared F (1 <= F <= 200) kinds of food and D (1 <= D <= 200) kinds of drink. Each kind of food or drink has certain amount, that is, how many people could this food or drink serve. Besides, You know there’re N (1 <= N <= 200) people and you too can tell people’s personal preference for food and drink.
Back to your goal: to serve as many people as possible. So you must decide a plan where some people are served while requirements of the rest of them are unmet. You should notice that, when one’s requirement is unmet, he/she would just go away, refusing any service.
The issue comes up as people in your college are more and more difficult to serve with meal: They eat only some certain kinds of food and drink, and with requirement unsatisfied, go away directly.
You have prepared F (1 <= F <= 200) kinds of food and D (1 <= D <= 200) kinds of drink. Each kind of food or drink has certain amount, that is, how many people could this food or drink serve. Besides, You know there’re N (1 <= N <= 200) people and you too can tell people’s personal preference for food and drink.
Back to your goal: to serve as many people as possible. So you must decide a plan where some people are served while requirements of the rest of them are unmet. You should notice that, when one’s requirement is unmet, he/she would just go away, refusing any service.
Input
There are several test cases.
For each test case, the first line contains three numbers: N,F,D, denoting the number of people, food, and drink.
The second line contains F integers, the ith number of which denotes amount of representative food.
The third line contains D integers, the ith number of which denotes amount of representative drink.
Following is N line, each consisting of a string of length F. e jth character in the ith one of these lines denotes whether people i would accept food j. “Y” for yes and “N” for no.
Following is N line, each consisting of a string of length D. e jth character in the ith one of these lines denotes whether people i would accept drink j. “Y” for yes and “N” for no.
Please process until EOF (End Of File).
For each test case, the first line contains three numbers: N,F,D, denoting the number of people, food, and drink.
The second line contains F integers, the ith number of which denotes amount of representative food.
The third line contains D integers, the ith number of which denotes amount of representative drink.
Following is N line, each consisting of a string of length F. e jth character in the ith one of these lines denotes whether people i would accept food j. “Y” for yes and “N” for no.
Following is N line, each consisting of a string of length D. e jth character in the ith one of these lines denotes whether people i would accept drink j. “Y” for yes and “N” for no.
Please process until EOF (End Of File).
Output
For each test case, please print a single line with one integer, the maximum number of people to be satisfied.
Sample Input
4 3 3
1 1 1
1 1 1
YYN
NYY
YNY
YNY
YNY
YYN
YYN
NNY
1 1 1
1 1 1
YYN
NYY
YNY
YNY
YNY
YYN
YYN
NNY
Sample Output
3
Source
题解：
建图：S-F-人-人-D-T
代码
//зїеп:1085422276
#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
#include <fstream>
#include <map>
#include <stack>
typedef __int64 ll;
using namespace std;
const int inf = ;
inline ll read()
{
ll x=,f=;
char ch=getchar();
while(ch<''||ch>'')
{
if(ch=='-')f=-;
ch=getchar();
}
while(ch>=''&&ch<='')
{
x=x*+ch-'';
ch=getchar();
}
return x*f;
} //*******************************
namespace NetFlow
{
const int MAXN=,MAXM=,inf=1e9;
struct Edge
{
int v,c,f,nx;
Edge() {}
Edge(int v,int c,int f,int nx):v(v),c(c),f(f),nx(nx) {}
} E[MAXM];
int G[MAXN],cur[MAXN],pre[MAXN],dis[MAXN],gap[MAXN],N,sz;
void init(int _n)
{
N=_n,sz=; memset(G,-,sizeof(G[])*N);
}
void link(int u,int v,int c)
{
E[sz]=Edge(v,c,,G[u]); G[u]=sz++;
E[sz]=Edge(u,,,G[v]); G[v]=sz++;
}
int ISAP(int S,int T)
{//S -> T
int maxflow=,aug=inf,flag=false,u,v;
for (int i=;i<N;++i)cur[i]=G[i],gap[i]=dis[i]=;
for (gap[S]=N,u=pre[S]=S;dis[S]<N;flag=false)
{
for (int &it=cur[u];~it;it=E[it].nx)
{
if (E[it].c>E[it].f&&dis[u]==dis[v=E[it].v]+)
{
if (aug>E[it].c-E[it].f) aug=E[it].c-E[it].f;
pre[v]=u,u=v; flag=true;
if (u==T)
{
for (maxflow+=aug;u!=S;)
{
E[cur[u=pre[u]]].f+=aug;
E[cur[u]^].f-=aug;
}
aug=inf;
}
break;
}
}
if (flag) continue;
int mx=N;
for (int it=G[u];~it;it=E[it].nx)
{
if (E[it].c>E[it].f&&dis[E[it].v]<mx)
{
mx=dis[E[it].v]; cur[u]=it;
}
}
if ((--gap[dis[u]])==) break;
++gap[dis[u]=mx+]; u=pre[u];
}
return maxflow;
}
bool bfs(int S,int T)
{
static int Q[MAXN]; memset(dis,-,sizeof(dis[])*N);
dis[S]=; Q[]=S;
for (int h=,t=,u,v,it;h<t;++h)
{
for (u=Q[h],it=G[u];~it;it=E[it].nx)
{
if (dis[v=E[it].v]==-&&E[it].c>E[it].f)
{
dis[v]=dis[u]+; Q[t++]=v;
}
}
}
return dis[T]!=-;
}
int dfs(int u,int T,int low)
{
if (u==T) return low;
int ret=,tmp,v;
for (int &it=cur[u];~it&&ret<low;it=E[it].nx)
{
if (dis[v=E[it].v]==dis[u]+&&E[it].c>E[it].f)
{
if (tmp=dfs(v,T,min(low-ret,E[it].c-E[it].f)))
{
ret+=tmp; E[it].f+=tmp; E[it^].f-=tmp;
}
}
}
if (!ret) dis[u]=-; return ret;
}
int dinic(int S,int T)
{
int maxflow=,tmp;
while (bfs(S,T))
{
memcpy(cur,G,sizeof(G[])*N);
while (tmp=dfs(S,T,inf)) maxflow+=tmp;
}
return maxflow;
}
}
using namespace NetFlow;
int main()
{
int n,f,d;
int fs,ds;
while(scanf("%d%d%d",&n,&f,&d)!=EOF){
init();
for(int i=;i<=f;i++)
{
fs=read();
link(,i,fs);
}
for(int i=;i<=d;i++)
{
ds=read();
link(i+,,ds);
}
char ch[];
for(int i=;i<=n;i++)
{
scanf("%s",ch);
for(int j=;j<f;j++)
{
if(ch[j]=='Y'){
link(j+,+i,);
}
}
}
for(int i=;i<=n;i++)
{
scanf("%s",ch);
for(int j=;j<d;j++)
{
if(ch[j]=='Y'){
link(+i,j++,);
}
}
}//
for(int i=;i<=n;i++)link(+i,+i,);
printf("%d\n",ISAP(,));//cout<<1111<<endl;
}
return ;
}