Submission #213456

#	Time	Username	Problem	Language	Result	Execution time	Memory
213456		Haunted_Cpp	Shell (info1cup18_shell)	C++17	100 / 100	345 ms	44148 KiB

shell

#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <cassert>
#include <string>
#include <cstring>
#include <bitset>
 
#define FOR(i, a, b) for(int i = a; i < (int) b; i++)
#define F0R(i, a) FOR (i, 0, a)
#define ROF(i, a, b) for(int i = a; i >= (int) b; i--)
#define R0F(i, a) ROF(i, a, 0)
#define GO(i, a) for (auto i : a)
 
#define rsz resize
#define eb emplace_back
#define pb push_back
#define sz(x) (int) x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define f first
#define s second
 
using namespace std;
 
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vpii;
typedef vector<vi> vvi;
typedef vector<vpii> vvpii;
typedef long long i64;
typedef vector<i64> vi64;
typedef vector<vi64> vvi64;
typedef pair<i64, i64> pi64;
typedef vector<pi64> vpi64;

const int dr[] = {+1, -1, +0, +0, +1, -1, +1, -1};
const int dc[] = {+0, +0, +1, -1, +1, -1, -1, +1};
const int ms[] = {+31, +29, +31, 30, +31, +30, +31, +31, +30, +31, +30, +31};

const int MOD = 1e9 + 7;
const int N = 1e6 + 5;

int add (int a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
  return a;
}

int mult (int a, int b) {
  i64 res = 1LL * a * b;
  if (res >= MOD) res %= MOD;
  return res;
}

vector<int> especial, deg (N), lvl (N);
vector<int> g [N];

int target_node, dp [N];

int dfs (int node) {
  if (node == target_node) return 1;
  if (lvl[node] >= lvl[target_node]) return 0;
  int &res = dp[node];
  if (~res) return res;
  res = 0;
  GO (to, g[node]) {
    res = add (res, dfs (to));
  }
  return res;
}

int main () {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int v, e, special;
  cin >> v >> e >> special;
  especial.eb(0);
  F0R (i, special) {
    int foo;
    cin >> foo;
    --foo;
    if (foo) especial.eb(foo);
  }
  if (especial.back() != v - 1) especial.eb(v - 1);
  F0R (i, e) {
    int st, et;
    cin >> st >> et;
    --st; --et;
    g[st].eb(et);
    ++deg[et];
  }
  queue<int> q;
  F0R (i, v) {
    if (!deg[i]) {
      q.push(i);
      lvl[i] = 0;
    }
  }
  while (!q.empty()) {
    int node = q.front();
    q.pop();
    GO (to, g[node]) {
      --deg[to];
      if (!deg[to]) {
        q.push(to);
        lvl[to] = lvl[node] + 1;
      }
    }
  }
  memset (dp, -1, sizeof(dp));
  int res = 1;
  R0F (i, sz(especial) - 2) { 
    int current_node = especial[i];
    target_node = especial[i + 1];
    res = mult (res, dfs (current_node));
  }
  cout << res << '\n';
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 45 / 45
• Subtask 3: 20 / 20
• Subtask 4: 25 / 25