BZOJ 1433 ZJOI 2009 假期的宿舍 最大流 Dinic

题目大意：一个住校的问题，给出那些人住校，那些人不住校，那些人和那些人认识，认识的人可以谁他的床，问能不能满足所有人都有床住。

思路：二分图最大匹配，当然也可以用网络流来做。建图方法如下：

1.住校的人向T连边

2.想睡的人从S连边

3.互相认识的人连边

然后跑最大流，判断是否满流，输出结果。

CODE：

#include <queue>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define MAX 110#define S 0#define T (points << 1|1)#define INF 0x3f3f3f3fusing namespace std;int cases,points;int map[MAX][MAX];int have_bed[MAX];int deep[MAX];bool BFS();int Dinic(int x,int flow);int main(){    for(cin >> cases;cases; --cases) {        scanf("%d",&points);        int cnt = 0;        memset(map,0,sizeof(map));        for(int i = 1;i <= points; ++i) {            scanf("%d",&have_bed[i]);            if(have_bed[i])    map[i + points][T] = 1;        }        for(int x,i = 1;i <= points; ++i) {            scanf("%d",&x);            if(!have_bed[i] || (have_bed[i] && !x))                map[S][i] = 1,cnt++;        }        for(int i = 1;i <= points; ++i)            for(int x,j = 1;j <= points; ++j) {                scanf("%d",&x);                if(x || i == j)                    map[i][j + points] = 1;            }        int ans = 0;        while(BFS())            ans += Dinic(S,INF);        if(ans == cnt)  puts("^_^");        else    puts("T_T");    }    return 0;}bool BFS(){    static queue<int> q;    while(!q.empty())   q.pop();    memset(deep,0,sizeof(deep));    deep[S] = 1;    q.push(S);    while(!q.empty()) {        int x = q.front(); q.pop();        for(int i = S;i <= T; ++i)            if(map[x][i] && !deep[i]) {                deep[i] = deep[x] + 1;                q.push(i);                if(i == T)  return true;            }    }    return false;}int Dinic(int x,int flow){    if(x == T)  return flow;    int temp = flow;    for(int i = S;i <= T; ++i)        if(deep[i] == deep[x] + 1 && map[x][i] && temp) {            int away = Dinic(i,min(temp,map[x][i]));            if(!away)   deep[i] = 0;            map[x][i] -= away;            map[i][x] += away;            temp -= away;        }    return flow - temp;}