POJ1149 网络流最大流

POJ1149 网络流最大流

#include <queue>
#include <cstring>
#include <cstdio>
using namespace std;
const int N = 1010;
struct node{
    int v, w, nxt;
}edge[N * N];
int s[N], fir[N], deep[N], vis[N];
int n, m, k, cnt, st, ed;
inline void add(int u, int v, int w){
    edge[++cnt] = (node){v, w, fir[u]}; fir[u] = cnt;
    edge[++cnt] = (node){u, 0, fir[v]}; fir[v] = cnt;
}
inline int bfs(){
    memset(deep, 0, sizeof(deep));
    deep[st] = 1;
    queue<int> q;
    q.push(st);
    while(!q.empty()){
        int u = q.front();
        q.pop();
        for(int i = fir[u]; i; i = edge[i].nxt){
            int v = edge[i].v;
            if(edge[i].w && !deep[v]){
                deep[v] = deep[u] + 1;
                q.push(v);
            }
        }
    }
    return deep[ed];
}
inline int dfs(int u, int fl){
    if(u == ed || fl == 0) return fl;
    int f = 0;
    for(int i = fir[u]; i; i = edge[i].nxt){
        int v = edge[i].v;
        if(edge[i].w && deep[u] + 1 == deep[v]){
            int x = dfs(v, min(fl, edge[i].w));
            edge[i].w -= x;
            edge[i^1].w += x;
            fl -= x;
            f += x;
        }
    }
    if(!f) deep[u] = -2;
    return f;
}
inline int Dinic(){
    int ans = 0, d;
    while(bfs()){
        while((d = dfs(st, 0x3f3f3f3f))){
            ans += d;
        }
    }
    return ans;
}
int main(){
#ifdef ONLINE_JUDGE
#else
    freopen("in.txt", "r", stdin);
#endif //ONLINE_JUDGE
    int a, b, c;
    while(~scanf("%d%d", &m, &n)){
        cnt = 1;
        st = 0, ed = n + 1;
        memset(fir, 0, sizeof(fir));
        memset(vis, 0, sizeof(vis));
        for(int i = 1; i <= m; i++){
            scanf("%d", &s[i]);
        }
        for(int i = 1; i <= n; i++){
            scanf("%d", &k);
            b = 0;
            for(int j = 1; j <= k; j++){
                scanf("%d", &a);
                if(!vis[a]) b += s[a];
                else add(vis[a], i, 0x3f3f3f3f);
                vis[a] = i;
            }
            add(st, i, b);
            scanf("%d", &c);
            add(i, ed, c);
        }
        int ans = Dinic();
        printf("%d\n", ans);
    }
    return 0;
}

posted on 2019-02-20 19:51  坤sir  阅读(79)  评论(0编辑  收藏  举报

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