HDU 4309 Seikimatsu Occult Tonneru——最大流

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
const int maxn = 200;
const int INF = 0x3f3f3f3f;
int n, m, s, t;
struct Edge { int from, to, flow, cap; };
struct Dinic {
    vector<Edge> edges;
    vector<int> G[maxn];
    int level[maxn], cur[maxn];
    void init() {
        edges.clear();
        for (int i = 0; i < maxn; i++) G[i].clear();
    }
    void addedge(int from, int to, int cap) {
        edges.push_back(Edge{from, to, 0, cap});
        edges.push_back(Edge{to, from, 0, 0});
        G[from].push_back(edges.size()-2);
        G[to].push_back(edges.size()-1);
    }
    int bfs() {
        memset(level, 0, sizeof(level));
        level[s] = 1;
        queue<int> q;
        q.push(s);
        while (!q.empty()) {
            int u = q.front(); q.pop();
            for (int i = 0; i < (int)G[u].size(); i++) {
                Edge &e = edges[G[u][i]];
                if (e.cap - e.flow > 0 && !level[e.to]) {
                    level[e.to] = level[u] + 1;
                    q.push(e.to);
                }
            }
        }
        return level[t];
    }
    int dfs(int u, int f) {
        if (u == t || !f) return f;
        for (int &i = cur[u]; i < (int)G[u].size(); i++) {
            Edge &e = edges[G[u][i]];
            if (e.cap - e.flow > 0 && level[e.to] == level[u] + 1) {
                int d = dfs(e.to, min(f, e.cap - e.flow));
                if (d > 0) {
                    e.flow += d;
                    edges[G[u][i]^1].flow -= d;
                    return d;
                }
            }
        }
        return 0;
    }
    int maxflow() {
        int ans = 0, f;
        while (bfs()) {
            memset(cur, 0, sizeof(cur));
            while((f = dfs(s, INF))) ans += f;
        }
        return ans;
    }
}ac;
int num[maxn], u[maxn], v[maxn], w[maxn], flag[maxn], a[maxn ], id[1010];
int main() {
    while (~scanf("%d%d", &n, &m)) {
        s = 0, t = n+50;
        for (int i = 1; i <= n; i++) scanf("%d", &num[i]);
        int cnt = 0, cnt_ = 0;
        for (int i = 1; i <= m; i++) {
            scanf("%d%d%d%d", &u[i], &v[i], &w[i], &flag[i]);
            if (flag[i] > 0) a[++cnt] = i;
            if (flag[i] < 0) id[i] = ++cnt_;
        }
        int ans = 0, cost = INF;
        for (int i = 0; i < (1<<cnt); i++) {
            int sum = 0;
            ac.init();
            for (int j = 1; j <= n; j++) if (num[j]) ac.addedge(s, j, num[j]);
            for (int j = 1; j <= m; j++) {
                if (flag[j] < 0) {
                    ac.addedge(u[j], id[j]+n, INF);
                    ac.addedge(id[j]+n, v[j], INF);
                    ac.addedge(id[j]+n, t, w[j]);
                }
                else if (flag[j] == 0) ac.addedge(u[j], v[j], INF);
                else ac.addedge(u[j], v[j], 1);
            }
            for (int j = 0; j < cnt; j++) {
                if (i & (1<<j)) {
                    sum += w[a[j+1]];
                    ac.addedge(u[a[j+1]], v[a[j+1]], INF);
                }
            }
            int x = ac.maxflow();
            if (x > ans) ans = x, cost = sum;
            else if (x == ans) cost = min(cost, sum);
        }
        if (ans == 0) printf("Poor Heaven Empire\n");
        else printf("%d %d\n", ans, cost);
    }
    return 0;
}