Submission #61392143

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

using ll = long long;

const int MAXN = 2025;
const ll MOD = 998244353LL;

int n, m, p[MAXN+2], viz[MAXN+2], real[MAXN+2];
long long ans = 1;
vector<int> stk, ch[MAXN+2];
ll dp[MAXN+2][MAXN+2];

void dfs(int node)
{
    for (int j = 1; j <= m; j++) {
        dp[node][j] = 1;
    }
    for (auto x : ch[node]) {
        dfs(x);
        ll suma = 0;
        for (int j = 1; j <= m; j++) {
            suma = (suma + dp[x][j]) % MOD;
            dp[node][j] = (dp[node][j] * suma) % MOD;
        }
    }
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> p[i];
        real[i] = i;
    }
    for (int i = 1; i <= n; i++) {
        if (!viz[i]) {
            int node = i;
            viz[node] = 1;
            stk.push_back(node);
            while (!viz[p[node]]) {
                node = p[node];
                viz[node] = 1;
                stk.push_back(node);
            }
            if (viz[p[node]] == 1) {
                int x = p[node];
                while (stk.back() != x) {
                    real[stk.back()] = x;
                    viz[stk.back()] = 2;
                    stk.pop_back();
                }
            }
            while (!stk.empty()) {
                viz[stk.back()] = 2;
                stk.pop_back();
            }
        }
    }
    for (int i = 1; i <= n; i++) {
        p[i] = real[p[i]];
        if (real[i] == i && p[i] != i) {
            ch[p[i]].push_back(i);
        }
    }
    for (int i = 1; i <= n; i++) {
        if (p[i] == i) {
            dfs(i);
            ll suma = 0;
            for (int j = 1; j <= m; j++) {
                suma = (suma + dp[i][j]) % MOD;
            }
            ans = (ans * suma) % MOD;
        }
    }
    cout << (ans % MOD + MOD) % MOD;
    return 0;
}

Submission Info

Judge Result