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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#188295#5487. Movie NightBeevo#WA 0ms3792kbC++202.5kb2023-09-25 18:28:492023-09-25 18:28:49

Judging History

你现在查看的是最新测评结果

  • [2023-09-25 18:28:49]
  • 评测
  • 测评结果:WA
  • 用时:0ms
  • 内存:3792kb
  • [2023-09-25 18:28:49]
  • 提交

answer

#include <bits/stdc++.h>

#define el '\n'
#define Beevo ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

typedef long long ll;
typedef long double ld;

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

const int M = 1e9 + 7;

int mul(int a, int b) {
    return 1LL * a * b % M;
}

int add(int a, int b) {
    b = (b + M) % M;

    return (a + b) % M;
}

vector<vector<int>> adj, adj_rev;
vector<bool> used;
vector<int> order, component;

void dfs1(int v) {
    used[v] = true;

    for (auto u : adj[v])
        if (!used[u])
            dfs1(u);

    order.push_back(v);
}

void dfs2(int v) {
    used[v] = true;
    component.push_back(v);

    for (auto u : adj_rev[v])
        if (!used[u])
            dfs2(u);
}

int dfs(int u, vector<vector<int>> &g) {
    if (g[u].empty())
        return 0;

    return dfs(g[u][0], g) + 1;
}

void testCase() {
    int n;
    cin >> n;

    adj.resize(n), adj_rev.resize(n);

    for (int i = 0; i < n; i++) {
        int a;
        cin >> a;
        a--;
        adj[i].push_back(a);
        adj_rev[a].push_back(i);
    }

    used.assign(n, false);

    for (int i = 0; i < n; i++)
        if (!used[i])
            dfs1(i);

    used.assign(n, false);
    reverse(order.begin(), order.end());

    vector<int> roots(n, 0);
    vector<int> root_nodes;
    vector<vector<int>> adj_scc(n);

    for (auto v : order)
        if (!used[v]) {
            dfs2(v);

            int root = component.front();
            for (auto u : component) roots[u] = root;
            root_nodes.push_back(root);

            component.clear();
        }


    vector<int> in(n);
    for (int v = 0; v < n; v++)
        for (auto u : adj[v]) {
            int root_v = roots[v],
                    root_u = roots[u];

            if (root_u != root_v)
                adj_scc[root_u].push_back(root_v), in[root_v]++;
        }

    int sol = 1;
    for (int i = 0; i < n; i++) {
        if (!in[i] && roots[i] == i) {
            if (adj_scc[i].empty()) {
                sol = mul(sol, 2);

                continue;
            }

            int cur = 1;
            for (auto &j: adj_scc[i])
                cur = mul(cur, dfs(j, adj_scc) + 1);

            sol = mul(sol, add(cur, 2));
        }
    }

    cout << add(sol, -1);
}

signed main() {
    Beevo

    int t = 1;
//    cin >> t;

    while (t--)
        testCase();
}

詳細信息

Test #1:

score: 100
Accepted
time: 0ms
memory: 3660kb

input:

4
2
3
4
3

output:

3

result:

ok single line: '3'

Test #2:

score: 0
Accepted
time: 0ms
memory: 3624kb

input:

5
2
3
1
5
4

output:

3

result:

ok single line: '3'

Test #3:

score: 0
Accepted
time: 0ms
memory: 3624kb

input:

6
2
4
2
6
1
3

output:

3

result:

ok single line: '3'

Test #4:

score: -100
Wrong Answer
time: 0ms
memory: 3792kb

input:

8
2
3
4
1
3
3
1
4

output:

2

result:

wrong answer 1st lines differ - expected: '16', found: '2'