[BZOJ1497][NOI2006]最大获利

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <algorithm>
using namespace std;
#define rep(i, s, t) for(int i = (s); i <= (t); i++)
#define dwn(i, s, t) for(int i = (s); i >= (t); i--)

int read() {
    int x = 0, f = 1; char c = getchar();
    while(!isdigit(c)){ if(c == ‘-‘) f = -1; c = getchar(); }
    while(isdigit(c)){ x = x * 10 + c - ‘0‘; c = getchar(); }
    return x * f;
}

#define maxn 55010
#define maxm 400010
#define oo 2147483647

struct Edge {
    int from, to, flow;
    Edge() {}
    Edge(int _1, int _2, int _3): from(_1), to(_2), flow(_3) {}
};
struct Dinic {
    int n, m, s, t, head[maxn], nxt[maxm];
    Edge es[maxm];
    int vis[maxn], Q[maxn], hd, tl;
    int cur[maxn];
    
    void init() {
        m = 0; memset(head, -1, sizeof(head));
        return ;
    }
    void setn(int _) {
        n = _;
        return ;
    }
    
    void AddEdge(int a, int b, int c) {
        es[m] = Edge(a, b, c); nxt[m] = head[a]; head[a] = m++;
        es[m] = Edge(b, a, 0); nxt[m] = head[b]; head[b] = m++;
        return ;
    }
    
    bool BFS() {
        memset(vis, 0, sizeof(vis));
        hd = tl = 0; Q[++tl] = t;
        vis[t] = 1;
        while(hd < tl) {
            int u = Q[++hd];
            for(int i = head[u]; i != -1; i = nxt[i]) {
                Edge& e = es[i^1];
                if(!vis[e.from] && e.flow) {
                    vis[e.from] = vis[u] + 1;
                    Q[++tl] = e.from;
                }
            }
        }
        return vis[s] > 0;
    }
    
    int DFS(int u, int a) {
        if(u == t || !a) return a;
        int flow = 0, f;
        for(int& i = cur[u]; i != -1; i = nxt[i]) {
            Edge& e = es[i];
            if(vis[e.to] == vis[u] - 1 && (f = DFS(e.to, min(a, e.flow)))) {
                flow += f; a -= f;
                e.flow -= f; es[i^1].flow += f;
                if(!a) return flow;
            }
        }
        return flow;
    }
    
    int MaxFlow(int _s, int _t) {
        s = _s; t = _t;
        int flow = 0;
        while(BFS()) {
            rep(i, 1, n) cur[i] = head[i];
            flow += DFS(s, oo);
        }
        return flow;
    }
} sol;

int CntP;
struct Point {
    int id;
    Point(): id(0) {}
    int p() { return id ? id : id = ++CntP; }
} node[maxn], per[maxn], S, T;

int main() {
    int n = read(), m = read();
    sol.init();
    rep(i, 1, n) sol.AddEdge(S.p(), node[i].p(), read());
    int ans = 0;
    rep(i, 1, m) {
        int a = read(), b = read(), c = read();
        sol.AddEdge(node[a].p(), per[i].p(), oo);
        sol.AddEdge(node[b].p(), per[i].p(), oo);
        sol.AddEdge(per[i].p(), T.p(), c);
        ans += c;
    }
    sol.setn(CntP);
    printf("%d\n", ans - sol.MaxFlow(S.p(), T.p()));
    
    return 0;
}