萌新,tarjan,50pts,WA14579,马蜂怪异,求助

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5 + 1;
const int maxm = 1e5 + 1;

template<typename T>
void print_array(T * bg, T * ed) {
    for (T * i = bg; i < ed; i++) {
        cout << *i << " ";
    }
    cout << endl;
}

struct edge {
    int from, to, next;
};

int trans[maxn];

namespace no_ring_graph {
    int n, m;
    int cnt_edge;
    int head[maxn];
    edge e[maxm];
    int val[maxn];
    int intime[maxn];
    int dp[maxn];

    void addedge(int u, int v) {
        e[++cnt_edge].to = v;
        e[cnt_edge].from = u;
        e[cnt_edge].next = head[u];
        head[u] = cnt_edge;
    }

    int get_max() {
        queue<int> que;
        int sum = 0;
        for (int i = 1; i <= n; i++) {
            if (!intime[i]) {
                que.push(i);
                dp[i] = val[i];
            }
        }
        int cur, mx = -2e9;
        while (!que.empty()) {
            cur = que.front();
            que.pop();
            for (int i = head[cur]; i; i = e[i].next) {
                int v = e[i].to;
                dp[v] = max(dp[v], dp[cur] + val[v]);
                intime[v]--;
                if (!intime[v]) {
                    que.push(v);
                }
            }
        }
        for (int i = 1; i <= n; i++) {
        	mx = max(mx, dp[i]);
		}
        return mx;
    }
}

namespace original_graph {
    int n, m;
    int cnt_edge;
    int head[maxn];
    edge e[maxm];
    int val[maxn];

    void addedge(int u, int v) {
        e[++cnt_edge].to = v;
        e[cnt_edge].from = u;
        e[cnt_edge].next = head[u];
        head[u] = cnt_edge;
    }

    int id;
    int vis[maxn];
    int dfn[maxn];
    int low[maxn];
    stack<int> path;
    vector<int> rings[maxn];
    int cnt_ring;

    void get_rings(int u, int fa) {
        dfn[u] = ++id;
        low[u] = dfn[u];
        vis[u] = true;
        path.push(u);
        for (int i = head[u]; i; i = e[i].next) {
            int v = e[i].to;
            if (vis[v]) {
                low[u] = min(low[u], dfn[v]);
            } else {
                get_rings(v, u);
                low[u] = min(low[u], low[v]);
            }
        }
        if (low[u] == dfn[u]) {
            cnt_ring++;
            int v;
            no_ring_graph::val[cnt_ring] = 0;
            while (u != v) {
                v = path.top();
                rings[cnt_ring].push_back(v);
                path.pop();
                trans[v] = cnt_ring;
                no_ring_graph::val[cnt_ring] += val[v];
            }
        }
    }
}

int main() {
    cin >> original_graph::n >> original_graph::m;
    for (int i = 1; i <= original_graph::n; i++) {
        cin >> original_graph::val[i];
    }
    for (int i = 1; i <= original_graph::m; i++) {
        int u, v;
        cin >> u >> v;
        original_graph::addedge(u, v);
    }
    for (int i = 1; i <= original_graph::n; i++) {
        if (!original_graph::vis[i]) {
            original_graph::get_rings(i, 0);
        }
    }
//    print_array(trans + 1, trans + 1 + original_graph::n);
//    print_array(no_ring_graph::val + 1, no_ring_graph::val + 1 + original_graph::cnt_ring);

    (no_ring_graph::n = original_graph::cnt_ring);
    for (int i = 1; i <= original_graph::m; i++) {
        int bg = trans[original_graph::e[i].from];
        int ed = trans[original_graph::e[i].to];
        if (bg == ed) continue;
        no_ring_graph::addedge(bg, ed);
        no_ring_graph::intime[ed]++;
    }
    cout << no_ring_graph::get_max() << endl;
    return 0;
}