#1030763 (C++17) No.2980 Planar Tree 2

• 問題: No.2980 Planar Tree 2
• ユーザー: shobonvip
• 提出日時: 2024-12-11 04:23:14
• 言語: C++17 (gcc 13.3.0 + boost 1.87.0)
• 結果: AC
• 実行時間: 115 ms / 2,000 ms
• コード長: 2,195 bytes
• コンパイル時間: 4,070 ms
• コンパイル使用メモリ: 257,228 KB
• 最終ジャッジ日時: 2025-02-26 11:56:33
• ジャッジサーバーID （参考情報）: judge4 / judge3

ファイルパターン	結果
other	AC * 30

ソースコード

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
/**
    author:  shobonvip
    created: 2024.12.11 04:17:32
**/
#include<bits/stdc++.h>
using namespace std;
//* ATCODER
#include<atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
//*/
/* BOOST MULTIPRECISION
#include<boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
//*/
typedef long long ll;
#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()
template <typename T> bool chmin(T &a, const T &b) {
    if (a <= b) return false;
    a = b;
    return true;
}
template <typename T> bool chmax(T &a, const T &b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T> T max(vector<T> &a){
    assert(!a.empty());
    T ret = a[0];
    for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
    return ret;
}
template <typename T> T min(vector<T> &a){
    assert(!a.empty());
    T ret = a[0];
    for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
    return ret;
}
template <typename T> T sum(vector<T> &a){
    T ret = 0;
    for (int i=0; i<(int)a.size(); i++) ret += a[i];
    return ret;
}
//defmodfact
const int COMinitMAX = 998244;
mint fact[COMinitMAX+1], factinv[COMinitMAX+1];
void modfact(){
    fact[0] = 1;
    for (int i=1; i<=COMinitMAX; i++){
        fact[i] = fact[i-1] * i;
    }
    factinv[COMinitMAX] = fact[COMinitMAX].inv();
    for (int i=COMinitMAX-1; i>=0; i--){
        factinv[i] = factinv[i+1] * (i+1);
    }
}
mint cmb(int a, int b){
    if (a<b || b<0) return mint(0);
    return fact[a]*factinv[b]*factinv[a-b];
}
//--------
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    modfact();
    int n; cin >> n;
    vector ikeru(n, vector<int>(0));
    rep(i,0,n-1) {
        int u, v; cin >> u >> v;
        u--; v--;
        ikeru[u].push_back(v);
        ikeru[v].push_back(u);
    }
    vector<mint> dp(n);
    auto dfs = [&](auto self, int i, int p) -> void {
        int cnt = 0;
        mint tar = 1;
        for (int j: ikeru[i]) {
            if (j == p) continue;
            self(self, j, i);
            cnt += 1;
            tar *= dp[j];
        }
        if (i == 0) {
            tar *= fact[cnt];
        }else{
            tar *= (cnt + 1) * fact[cnt];
        }
        dp[i] = tar;
    };
    dfs(dfs, 0, -1);
    mint ans = dp[0] * factinv[n-1];
    cout << ans.val() << '\n';
    
}
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX