#1178210 (C++17) No.3635 Probability trip

• 問題: No.3635 Probability trip
• ユーザー: 👑 AngrySadEight
• 提出日時: 2026-08-21 22:28:43
• 言語: C++17 (gcc 15.2.0 + boost 1.90.0)
• 結果: AC
• 実行時間: 165 ms / 2,000 ms
• コード長: 4,734 bytes
• コンパイル時間: 2,569 ms
• コンパイル使用メモリ: 219,524 KB
• 実行使用メモリ: 9,384 KB
• 最終ジャッジ日時: 2026-08-21 22:28:58
• 合計ジャッジ時間: 7,323 ms
• ジャッジサーバーID （参考情報）: judge1_0 / judge3_0

ファイルパターン	結果
sample	AC * 3
other	AC * 43

ソースコード

#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

using mint = modint998244353;

void debug_mint1(vector<mint> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        cerr << vec[i].val() << " ";
    }
    cerr << endl;
}

void debug_mint2(vector<vector<mint>> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        for (int j = 0; j < vec[i].size(); j++) {
            cerr << vec[i][j].val() << " ";
        }
        cerr << endl;
    }
}

// 行列累乗ライブラリ
// m_mul と p_mul を同時にインポートする

vector<vector<ll>> m_mul(vector<vector<ll>> &a, vector<vector<ll>> &b, ll mod) {
    ll n = a.size();
    vector<vector<ll>> ret(n, vector<ll>(n, 0));
    for (ll i = 0; i < n; i++) {
        for (ll j = 0; j < n; j++) {
            for (ll k = 0; k < n; k++) {
                ret[i][j] = (ret[i][j] + a[i][k] * b[k][j]) % mod;
            }
        }
    }
    return ret;
}

vector<vector<ll>> p_mul(vector<vector<ll>> a, ll k, ll mod) {
    ll n = a.size();
    vector<vector<ll>> ret(n, vector<ll>(n, 0));
    for (ll i = 0; i < n; i++) {
        ret[i][i] = 1;
    }
    while (k > 0) {
        if (k % 2 == 1) {
            ret = m_mul(a, ret, mod);
        }
        a = m_mul(a, a, mod);
        k /= 2;
    }
    return ret;
}

int main() {
    ll N, M;
    cin >> N >> M;
    vector<ll> u(M);
    vector<ll> v(M);
    rep(i, M){
        cin >> u[i] >> v[i];
        u[i]--;
        v[i]--;
    }
    ll S, T, A, B;
    cin >> S >> T >> A >> B;
    A--;
    B--;

    vector<vector<ll>> graph(N, vector<ll>(0));
    rep(i, M){
        graph[u[i]].push_back(v[i]);
        graph[v[i]].push_back(u[i]);
    }

    // 次の日に選ぶ道ごとの確率を持つ
    vector<vector<ll>> Mat(N, vector<ll>(N, 0));
    for (ll i = 0; i < N; i++){
        ll len = graph[i].size();
        ll rate = (mint(1) / mint(len)).val();
        for (ll j = 0; j < len; j++){
            Mat[i][graph[i][j]] = rate;
        }
    }
    // debug(Mat);
    
    vector<vector<ll>> Mat1 = p_mul(Mat, S - 1, mod2);
    vector<vector<ll>> Mat2 = p_mul(Mat, T - 1, mod2);
    vector<vector<ll>> Mat3 = p_mul(Mat, S - T, mod2);

    ll rate1 = Mat1[0][A];
    ll rate2 = Mat2[0][B];
    ll rate3 = Mat3[B][A];

    mint ans = mint(rate2) * mint(rate3) / mint(rate1);
    cout << ans.val() << endl;
}