ZOJ 2788 Panic Room 最小割

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define maxn 410
#define maxm 40003
#define inf 1000000000

int min(int a, int b)
{
    return a < b ? a : b;
}
struct E
{
    int v, next, c;
}edge[maxm];

int head[maxn], tot;
int n, m;
int S, T;

void add(int s, int t, int c)
{
    edge[tot].v = t;
    edge[tot].c = c;
    edge[tot].next = head[s];
    head[s] = tot++;
    edge[tot].v = s;
    edge[tot].c = 0;
    edge[tot].next = head[t];
    head[t] = tot++;
}

void init()
{
    tot = 0;
    memset(head, -1, sizeof(head));
}

int gap[maxn], dis[maxn], pre[maxn], cur[maxn];

int sap(int s, int t, int vs)// s 源点，t汇点，vs顶点总数
{
    int i;
    for(i = 0; i <= vs; i++)
    {
        dis[i] = gap[i] = 0;
        cur[i] = head[i];
    }
    gap[0] = vs;
    int u = pre[s] = s, maxf = 0, aug = inf, v;
    while(dis[s] < vs)
    {
loop:   for(i = cur[u]; i != -1; i = edge[i].next)
        {
            v = edge[i].v;
            if(edge[i].c > 0 && dis[u] == dis[v] + 1)
            {
                aug = min(aug, edge[i].c);
                pre[v] = u;
                cur[u] = i; 
                u = v;
                if(u == t)
                {
                    while(u != s)
                    {
                        u = pre[u];
                        edge[cur[u]].c -= aug;
                        edge[cur[u]^1].c += aug;
                    }
                    maxf += aug;
                    aug = inf;
                }
                goto loop;
            }
        }
        int min_d = vs;
        for(i = head[u]; i != -1; i = edge[i].next)
        {
            v = edge[i].v;
            if(edge[i].c > 0 && dis[v] < min_d)
            {
                min_d = dis[v];
                cur[u] = i;
            }
        }
        if( !(--gap[dis[u]])) break;
        ++gap[dis[u] = min_d + 1];
        u = pre[u];
    }
    return maxf;
}

int main()
{
    int i, j, k, cas;
    scanf("%d", &cas);
    char buf[11];
    int x;
    while(cas--)
    {
        scanf("%d%d", &n, &m);
        init();
        S = n; T = m;
        for(i = 0; i < n; i++)
        {
            scanf("%s%d", buf, &k);
            if(buf[0] == 'I')
                add(S, i, inf);
            while(k--)
            {
                scanf("%d", &x);
                add(i, x, inf);
                add(x, i, 1);
            }
        }
        int flow = sap(S, T, n+1);
        if(flow >= inf) printf("PANIC ROOM BREACH\n");
        else printf("%d\n", flow);
    }
    return 0;
}