CF1704E Count Seconds

#include<bits/stdc++.h>
#define int long long
#define mod 998244353
using namespace std;
int T = 0;
int n = 0 , m = 0 , cnt = 0 , ans = 0;
array<int , 200100> head , val , add , ind , out;
struct Node{
	int to;
	int nxt;
};
array<Node , 4000100> edge;
queue<int> q;
void new_line(int a , int b)
{
	edge[++ cnt].to = b;
	edge[cnt].nxt = head[a];
	head[a] = cnt;
	return;
} 
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	cin >> T;
	while(T --)
	{
		cin >> n >> m;
		ans = 0;
		int sum = 0;
		fill(head.data() + 1 , head.data() + n + 1 , 0);
		fill(add.data() + 1 , add.data() + n + 1 , 0);
		fill(out.data() + 1 , out.data() + n + 1 , 0);
		fill(val.data() + 1 , val.data() + n + 1 , 0);
		fill(ind.data() + 1 , ind.data() + n + 1 , 0);
		fill(edge.data() + 1 , edge.data() + m + 1 , Node{0 , 0});
		for(int i = 1;i <= n;++ i)
		{
			cin >> val[i];
			sum += val[i];
		}
		for(int i = 1;i <= m;++ i)
		{
			int x = 0 , y = 0;
			cin >> x >> y;
			new_line(x , y);
			++ ind[y];
			++ out[x];
		}
		if(sum == 0)
		{
			cout << "0" << endl;
			continue;
		}
		for(int i = 1;i <= n;++ i)
		{
			bool check = 0;
			fill(add.data() + 1 , add.data() + n + 1 , 0);
			for(int x = 1;x <= n;++ x)
			{
				if(!val[x]) continue;
				for(int e = head[x];e;e = edge[e].nxt)
				{
					int to = edge[e].to;
					++ add[to];
				}
			}
			for(int x = 1;x <= n;++ x)
			{
				if(val[x] > 0) -- val[x];
			}
			for(int x = 1;x <= n;++ x)
			{
				val[x] += add[x];
				if(val[x] != 0)
				{
					check = 1;
				}
			}
			if(!check)
			{
				ans = i;
				break;
			}
		}
		if(ans != 0)
		{
			cout << ans << endl;
			continue;
		}
		for(int i = 1;i <= n;++ i)
		{
			val[i] %= mod;
		}
		for(int i = 1;i <= n;++ i)
		{
			if(!ind[i])
			{
				q.push(i);
			}
		}
		int t = 0;
		for(int i = 1;i <= n;++ i)
		{
			if(!out[i]) t = i;
		}
		while(!q.empty())
		{
			int x = q.front();
			q.pop();
			for(int e = head[x];e;e = edge[e].nxt)
			{
				int to = edge[e].to;
				val[to] += val[x];
				val[to] %= mod;
				-- ind[to];
				if(!ind[to]) q.push(to);
			}
		}
		cout << (val[t] + n % mod) % mod << endl;
	}
	return 0;
}

CF1704E Count Seconds 为什么统计答案是$val_t + n$ 不是 $\operatorname{max}{val_{1 \rightarrow n}} + n$