結果

問題 No.1507 Road Blocked
ユーザー ゆにぽけゆにぽけ
提出日時 2023-10-15 17:19:48
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 92 ms / 2,000 ms
コード長 3,048 bytes
コンパイル時間 1,156 ms
コンパイル使用メモリ 130,004 KB
実行使用メモリ 17,068 KB
最終ジャッジ日時 2024-09-16 22:04:16
合計ジャッジ時間 5,655 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
7,536 KB
testcase_01 AC 3 ms
6,940 KB
testcase_02 AC 3 ms
7,076 KB
testcase_03 AC 74 ms
17,068 KB
testcase_04 AC 78 ms
10,972 KB
testcase_05 AC 78 ms
10,860 KB
testcase_06 AC 79 ms
10,964 KB
testcase_07 AC 79 ms
10,740 KB
testcase_08 AC 79 ms
10,984 KB
testcase_09 AC 80 ms
10,980 KB
testcase_10 AC 88 ms
10,932 KB
testcase_11 AC 86 ms
10,748 KB
testcase_12 AC 92 ms
10,784 KB
testcase_13 AC 92 ms
10,924 KB
testcase_14 AC 84 ms
10,832 KB
testcase_15 AC 79 ms
10,960 KB
testcase_16 AC 77 ms
10,952 KB
testcase_17 AC 78 ms
10,916 KB
testcase_18 AC 77 ms
10,892 KB
testcase_19 AC 83 ms
10,816 KB
testcase_20 AC 83 ms
10,756 KB
testcase_21 AC 84 ms
10,916 KB
testcase_22 AC 82 ms
11,172 KB
testcase_23 AC 83 ms
11,096 KB
testcase_24 AC 84 ms
10,784 KB
testcase_25 AC 80 ms
11,004 KB
testcase_26 AC 80 ms
10,856 KB
testcase_27 AC 78 ms
10,796 KB
testcase_28 AC 79 ms
10,900 KB
testcase_29 AC 81 ms
10,984 KB
testcase_30 AC 80 ms
10,756 KB
testcase_31 AC 78 ms
11,184 KB
testcase_32 AC 79 ms
10,916 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cassert>
#include<cmath>
#include<ctime>
#include<iomanip>
#include<numeric>
#include<stack>
#include<queue>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<bitset>
#include<random>
using namespace std;
template<int m> struct modint
{
	private:
	unsigned int value;
	static constexpr int mod() {return m;}

	public:
	constexpr modint(const long long x = 0) noexcept
	{
		long long y = x;
		if(y < 0 || y >= mod())
		{
			y %= mod();
			if(y < 0) y += mod();
		}
		value = (unsigned int)y;
	}
	constexpr unsigned int val() noexcept {return value;}
	constexpr modint &operator+=(const modint &other) noexcept
	{
		value += other.value;
		if(value >= mod()) value -= mod();
		return *this;
	}
	constexpr modint &operator-=(const modint &other) noexcept
	{
		unsigned int x = value;
		if(x < other.value) x += mod();
		x -= other.value;
		value = x;
		return *this;
	}
	constexpr modint &operator*=(const modint &other) noexcept
	{
		unsigned long long x = value;
		x *= other.value;
		value = (unsigned int) (x % mod());
		return *this;
	}
	constexpr modint &operator/=(const modint &other) noexcept
	{
		return *this *= other.inverse();
	}
	constexpr modint inverse() const noexcept
	{
		assert(value);
		long long a = value,b = mod(),x = 1,y = 0;
		while(b)
		{
			long long q = a/b;
			a -= q*b; swap(a,b);
			x -= q*y; swap(x,y);
		}
		return modint(x);
	}
	constexpr modint power(long long N) const noexcept
	{
		assert(N >= 0);
		modint p = *this,ret = 1;
		while(N)
		{
			if(N & 1) ret *= p;
			p *= p;
			N >>= 1;
		}
		return ret;
	}
	constexpr modint operator+() {return *this;}
	constexpr modint operator-() {return modint() - *this;}
	constexpr modint &operator++(int) noexcept {return *this += 1;}
	constexpr modint &operator--(int) noexcept {return *this -= 1;}
	friend modint operator+(const modint& lhs, const modint& rhs) {return modint(lhs) += rhs;}
	friend modint operator-(const modint& lhs, const modint& rhs) {return modint(lhs) -= rhs;}
	friend modint operator*(const modint& lhs, const modint& rhs) {return modint(lhs) *= rhs;}
	friend modint operator/(const modint& lhs, const modint& rhs) {return modint(lhs) /= rhs;}
	friend ostream &operator<<(ostream &os,const modint &x) {return os << x.value;}
};
using mint = modint<998244353>;
//using mint = modint<1000000007>;
int N,ch[1 << 17],U[1 << 17],V[1 << 17];
vector<int> G[1 << 17];
void dfs(int u,int p)
{
	ch[u] = 1;
	for(int v:G[u]) if(v != p)
	{
		dfs(v,u);
		ch[u] += ch[v];
	}
}
void solve()
{
	cin >> N;
	for(int i = 1;i < N;i++)
	{
		int u,v;
		cin >> u >> v;
		u--; v--;
		U[i] = u,V[i]= v;
		G[u].push_back(v);
		G[v].push_back(u);
	}
	dfs(0,-1);
	mint ans = 0;
	for(int i = 1;i < N;i++)
	{
		int u = U[i],v = V[i];
		if(ch[u] > ch[v]) swap(u,v);
		ans += 1-mint(ch[u])*(N-ch[u])*2/N/(N-1);
	}
	ans /= N-1;
	cout << ans << endl;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int tt = 1;
	//cin >> tt;
	while(tt--) solve();
}
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