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Submission #1003125

# Submission time Handle Problem Language Result Execution time Memory
1003125 2024-06-20T06:26:57 Z vjudge1 Subtree (INOI20_subtree) C++17
12 / 100
 64 ms 32084 KB 
#include <bits/stdc++.h>
 
using namespace std;
 
#define int long long
#define inf 0x3F3F3F3F3F3F3F3F
 
const int MXN = 1e5 + 5;
const int LOG = 20;
const int mod = 1e9 + 7;

vector<int> adj[MXN];
vector<array<int, 2>> g[MXN];
int p[MXN], used[MXN], down[MXN], bak[MXN];
int in[MXN], t[MXN], tim;
int dp[MXN];

void _init(int a)
{
  t[a] = ++tim;
  used[a] = 1;
  for (array<int, 2> &v : g[a])
  {
    if (v[0] != p[a] && used[v[0]]) bak[v[1]] = 1;
  }
  for (array<int, 2> &v : g[a])
  {
    if (!used[v[0]]) 
    {
      p[v[0]] = a;
      _init(v[0]);
    }
  }
}

void dfs(int a)
{
  for (int &v : adj[a])
  {
    dfs(v);
  }
  if (down[a])
  {
    vector<int> path;
    int x = down[a];
    while (x)
    {
      path.push_back(x);
      in[x] = 1;
      if (x == a) break;
      else assert(!down[x]);
      x = p[x];
    }
    reverse(path.begin(), path.end());
    vector<int> sum(path.size(), 0);
    int co = 1;
    for (int i = (int)path.size() - 1; i >= 0; i--)
    {
      if (i == (int)path.size() - 1) co = (co * dp[path[i]]) % mod;
      else
      {
        for (int &v : adj[path[i]]) 
        {
          if (!in[v] && v == p[path[i]]) co = (co * (dp[v] + 1)) % mod;
        }
      }
      sum[i] = ((i + 1 < path.size() ? sum[i + 1] : 0) + co) % mod;
    }
    co = 1;
    for (int i = 0; i + 1 < path.size(); i++)
    {
      for (int &v : adj[path[i]])
      {
        if (!in[v] && v != p[path[i]]) 
        {
          co = (co * (dp[v] + 1)) % mod;
        }
      }
      dp[a] = (dp[a] + co) % mod;
      if (i + 2 < path.size()) dp[a] = (dp[a] + ((sum[i + 2] * co) % mod)) % mod;
    }
    for (int x : path) in[x] = 0;
  }
  else
  {
    dp[a] = 1;
    for (int &v : adj[a])
    {
      dp[a] = (dp[a] * (dp[v] + 1)) % mod;
    }
  }
}

signed main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= m; i++)
  {
    int u, v;
    cin >> u >> v;
    g[u].push_back({v, i});
    g[v].push_back({u, i});
  }
  _init(1);
  for (int a = 1; a <= n; a++)
  {
    for (array<int, 2> &v : g[a])
    {
      if (t[v[0]] > t[a] && !bak[v[1]]) adj[a].push_back(v[0]);
      else if (t[v[0]] > t[a] && bak[v[1]]) down[a] = v[0];
    }
  }
  dfs(1);
  int res = 0;
  for (int i = 1; i <= n; i++)
  {
    res = (res + dp[i]) % mod;
  }
  cout << res << '\n';
}

Compilation message

Main.cpp: In function 'void dfs(long long int)':
Main.cpp:67:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |       sum[i] = ((i + 1 < path.size() ? sum[i + 1] : 0) + co) % mod;
      |                  ~~~~~~^~~~~~~~~~~~~
Main.cpp:70:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |     for (int i = 0; i + 1 < path.size(); i++)
      |                     ~~~~~~^~~~~~~~~~~~~
Main.cpp:80:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |       if (i + 2 < path.size()) dp[a] = (dp[a] + ((sum[i + 2] * co) % mod)) % mod;
      |           ~~~~~~^~~~~~~~~~~~~

Subtask #1
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5208 KB Output is correct
2 Correct 3 ms 4952 KB Output is correct
3 Correct 2 ms 4956 KB Output is correct
4 Correct 2 ms 4956 KB Output is correct
5 Correct 2 ms 4956 KB Output is correct
6 Correct 3 ms 4956 KB Output is correct
7 Correct 2 ms 4952 KB Output is correct
8 Correct 2 ms 4952 KB Output is correct
9 Correct 2 ms 4952 KB Output is correct
10 Correct 2 ms 4956 KB Output is correct
11 Correct 2 ms 4956 KB Output is correct
12 Correct 2 ms 5056 KB Output is correct
13 Incorrect 2 ms 4956 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4952 KB Output is correct
2 Correct 5 ms 6232 KB Output is correct
3 Correct 39 ms 16432 KB Output is correct
4 Correct 47 ms 16428 KB Output is correct
5 Correct 38 ms 16208 KB Output is correct
6 Correct 50 ms 16212 KB Output is correct
7 Correct 57 ms 28496 KB Output is correct
8 Correct 51 ms 23808 KB Output is correct
9 Correct 47 ms 23632 KB Output is correct
10 Correct 33 ms 15452 KB Output is correct
11 Correct 35 ms 15812 KB Output is correct
12 Correct 58 ms 16996 KB Output is correct
13 Correct 64 ms 17488 KB Output is correct
14 Correct 40 ms 20672 KB Output is correct
15 Correct 54 ms 30156 KB Output is correct
16 Correct 56 ms 32084 KB Output is correct
17 Correct 53 ms 17492 KB Output is correct
18 Correct 45 ms 17520 KB Output is correct
19 Correct 51 ms 17492 KB Output is correct
20 Correct 27 ms 15564 KB Output is correct
21 Correct 36 ms 14944 KB Output is correct
22 Correct 36 ms 14932 KB Output is correct

Subtask #3
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5208 KB Output is correct
2 Correct 3 ms 4952 KB Output is correct
3 Correct 2 ms 4956 KB Output is correct
4 Correct 2 ms 4956 KB Output is correct
5 Correct 2 ms 4956 KB Output is correct
6 Correct 3 ms 4956 KB Output is correct
7 Correct 2 ms 4952 KB Output is correct
8 Correct 2 ms 4952 KB Output is correct
9 Correct 2 ms 4952 KB Output is correct
10 Correct 2 ms 4956 KB Output is correct
11 Correct 2 ms 4956 KB Output is correct
12 Correct 2 ms 5056 KB Output is correct
13 Incorrect 2 ms 4956 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #4
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5208 KB Output is correct
2 Correct 3 ms 4952 KB Output is correct
3 Correct 2 ms 4956 KB Output is correct
4 Correct 2 ms 4956 KB Output is correct
5 Correct 2 ms 4956 KB Output is correct
6 Correct 3 ms 4956 KB Output is correct
7 Correct 2 ms 4952 KB Output is correct
8 Correct 2 ms 4952 KB Output is correct
9 Correct 2 ms 4952 KB Output is correct
10 Correct 2 ms 4956 KB Output is correct
11 Correct 2 ms 4956 KB Output is correct
12 Correct 2 ms 5056 KB Output is correct
13 Incorrect 2 ms 4956 KB Output isn't correct
14 Halted 0 ms 0 KB -