#include <iostream>#include <queue>#include <cstdio>#include <string.h>using namespace std;#define N 100100#define M 1000100#define INF 1<<29struct node{ int v; int next;} edge[M];int dp[N]; // 最大价值 int enext[N]; //记录节点int indegree[N]; //入度int cost[N]; //价值int res;int idx;std::queue<int > q;int m,n,a,b,i,j;void input(){ for(i=1;i<=n;i++) { scanf("%d",&cost[i]); dp[i] = -INF; indegree[i] = 0; } idx=0; memset(enext,-1,sizeof(enext) ); for(i=1;i<=m;i++) { scanf("%d %d",&a,&b); edge[idx].v = b; edge[idx].next = enext[a]; enext[a] = idx++; indegree[b]++; } while( !q.empty() ) q.pop(); for( i=1;i<=n;i++) if( !indegree[i] ) q.push(i),dp[i]=cost[i];}int dag(){ res = -INF; while( !q.empty() ) { int cur = q.front(); q.pop(); bool flag = true; int nextid; for( i=enext[cur] ; i != -1 ; i = edge[i].next) { flag = false; nextid = edge[i].v ; if( dp[nextid] < cost[ nextid ] + dp[cur]) dp[nextid] = cost[nextid] + dp[cur]; indegree[nextid]--; if( !indegree[nextid] ) { q.push(nextid); } } if( flag && dp[cur] > res ) res = dp[cur]; } return res;}int main(){ while(scanf("%d %d",&n,&m) != EOF) { input(); printf("%dn",dag()); } return 0;}
