文件目录

#include <bits/stdc++.h>
using namespace std;
int n, m, u, v;
int a[100005];
vector<int> e[100005]; // 邻接表
int ind[100005];       // 拓扑排序 入度
int dp[100005][15];    // 状态：到达i节点，末尾为j的最长长度
int main()
{
    scanf("%d %d", &n, &m);
    for (int i = 1; i <= n; i++)
        scanf("%d", a + i);
    for (int i = 1; i <= m; i++)
    {
        scanf("%d %d", &u, &v);
        e[u].push_back(v);
        ind[v]++;
    }
    // 拓扑排序
    queue<int> q;
    for (int i = 1; i <= n; i++)
    {
        if (ind[i] == 0)
            q.push(i);
        dp[i][a[i]] = 1;
    }
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for (int i = 0; i < e[u].size(); i++)
        {
            int v = e[u][i];
            ind[v]--;
            if (ind[v] == 0)
                q.push(v);
            // 状态转移
            for (int i = 1; i <= a[v]; i++)
                if (dp[u][i] + 1 > dp[v][a[v]])
                    dp[v][a[v]] = dp[u][i] + 1;
            for (int i = 1; i <= 10; i++)
                if (dp[u][i] > dp[v][i])
                    dp[v][i] = dp[u][i];
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= 10; j++)
            ans = max(ans, dp[i][j]);
    cout << ans;
    return 0;
}