HDU 3249 Test for job (longest, DP) on a forward-free graph

Solving the problem: finding the longest road in a direction-free graph, simple dynamic programming

#include <iostream> #include <cstring> #include <cstdlib> #include <cstdio> #include <  algorithm> #include <vector> #include <cmath> #define LL long longusing namespace Std;const int maxn = 100000 + 10;const int maxm = 1000000 + 10;const LL INF =-1 * 20000 * 100000-10;struct edge{int to, next;} Edge[maxm];int tot, HEAD[MAXN]; LL W[MAXN];    LL Dp[maxn];int OUT[MAXN], vis[maxn];int N, m;void init () {tot = 0;    Memset (Head,-1, sizeof (head));    memset (w, 0, sizeof (w));    Memset (DP, INF, sizeof (DP));    memset (Vis, 0, sizeof (VIS)); memset (out, 0, sizeof);}    void Addedge (int u, int v) {edge[tot].to = v;    Edge[tot].next = Head[u]; Head[u] = tot++;}    int dfs (int u) {//cout << u << endl;    if (Vis[u]) return dp[u];    Vis[u] = 1;        for (int i=head[u];i!=-1;i=edge[i].next) {int v = edge[i].to;    Dp[u] = max (Dp[u], (LL) Dfs (v));    } if (head[u] = = 1) return dp[u] = W[u]; else return dp[u] = (Dp[u] + w[u]);   return dp[u];}        int main () {while (scanf ("%d%d", &n, &m)!=eof) {init ();        for (int i=1;i<=n;i++) scanf ("%d", &w[i]);        int u, v;            for (int i=1;i<=m;i++) {scanf ("%d%d", &u, &v);            Addedge (V, u);        out[u]++;        } LL ans = INF;        for (int i=1;i<=n;i++) cout << dp[i] << ";        for (int i=1;i<=n;i++) if (!out[i]) ans = max (ans, (LL) DFS (i));    printf ("%d\n", ans); } return 0;}

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HDU 3249 Test for job (longest, DP) on a forward-free graph