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#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N = 1e4+10, M = 1e5+10;
struct {
int v, next;
} e[M];
int n, m, p[N], dp[N], ans;
int cnt, head[N];
int top, stack[N];
int indexx, num, dfn[N], low[N], color[N], sum[N];
int heads = 1, tail, indegree[N], que[N];
bool instack[N];
void init()
{
memset(head, -1, sizeof head);
}
void add(int u,int v)
{
e[++cnt].next = head[u];
e[cnt].v = v;
head[u] = cnt;
return;
}
void tarjan(int u) {
int i;
dfn[u] = low[u] = ++indexx;
stack[++top] = u;
instack[u] = true;
for (i = head[u]; i+1; i = e[i].next) {
int v = e[i].v;
if (!dfn[v]) {
tarjan(v);
low[u] = min(low[u], low[v]);
}
else if (instack[v]) low[u] = min(low[u], dfn[v]);
}
if (dfn[u] == low[u]) {
num++;
do {
color[stack[top]] = num;
sum[num] += p[stack[top]];
instack[stack[top]] = false;
} while (stack[top--] != u);
}
return ;
}
void clear() {
memset(e, 0, sizeof(e));
init();
cnt = 0;
return ;
}
int topo()
{
for(int i=1;i<=num;i++)
{
if(!indegree[i])
{
que[++tail]=i;
dp[i]=sum[i];
}
}
while(tail>=heads)
{
int u=que[heads];
heads++;
for(int i=head[u];i+1;i=e[i].next)
{
int v=e[i].v;
dp[v]=max(dp[v],dp[u]+sum[v]);
indegree[v]--;
if(!indegree[v])
{
que[++tail]=v;
}
}
}
for (int i = 1; i <= num; i++)
ans = max(ans, dp[i]);
return ans;
}
int main()
{
init();
int i, a[M], b[M];
cin >> n >> m;
for (int i = 1; i <= n;i++)
cin >> p[i];
for (int i = 1; i <= m;i++)
{
cin >> a[i] >> b[i];
add(a[i], b[i]);
}
for (int i = 1; i <= n;i++)
{
if(!dfn[i])
tarjan(i);
}
clear();
for (int i = 1; i <= m;i++)
{
if(color[a[i]]!=color[b[i]])
{
add(color[a[i]], color[b[i]]);
indegree[color[b[i]]]++;
}
}
cout << topo() << endl;
}
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