結果

問題 No.1103 Directed Length Sum
ユーザー tkmst201tkmst201
提出日時 2020-12-01 16:51:52
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 771 ms / 3,000 ms
コード長 4,178 bytes
コンパイル時間 5,046 ms
コンパイル使用メモリ 205,364 KB
実行使用メモリ 107,728 KB
最終ジャッジ日時 2023-10-11 03:38:57
合計ジャッジ時間 13,801 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge13
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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
4,356 KB
testcase_01 AC 1 ms
4,352 KB
testcase_02 AC 331 ms
107,728 KB
testcase_03 AC 192 ms
42,280 KB
testcase_04 AC 411 ms
32,084 KB
testcase_05 AC 771 ms
53,080 KB
testcase_06 AC 253 ms
21,920 KB
testcase_07 AC 39 ms
7,696 KB
testcase_08 AC 66 ms
9,984 KB
testcase_09 AC 25 ms
6,028 KB
testcase_10 AC 108 ms
12,640 KB
testcase_11 AC 449 ms
34,640 KB
testcase_12 AC 252 ms
22,172 KB
testcase_13 AC 110 ms
12,824 KB
testcase_14 AC 17 ms
5,316 KB
testcase_15 AC 187 ms
18,108 KB
testcase_16 AC 523 ms
38,540 KB
testcase_17 AC 541 ms
40,108 KB
testcase_18 AC 113 ms
12,556 KB
testcase_19 AC 470 ms
35,328 KB
testcase_20 AC 31 ms
6,544 KB
testcase_21 AC 64 ms
9,276 KB
testcase_22 AC 370 ms
29,524 KB
testcase_23 AC 217 ms
18,948 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 <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

template<int M>
struct ModInt {
	static_assert(M > 0);
	
public:
	using value_type = int;
	using calc_type = std::int_fast64_t;
	
private:
	value_type val_;
	
public:
	constexpr ModInt(calc_type val = 0) : val_(val < 0 ? (val % M + M) % M : val % M) {}
	constexpr const value_type & val() const noexcept { return val_; }
	constexpr static decltype(M) mod() noexcept { return M; }
	
	explicit constexpr operator bool() const noexcept { return val_; }
	constexpr bool operator !() const noexcept { return !static_cast<bool>(*this); }
	constexpr ModInt operator +() const noexcept { return ModInt(*this); }
	constexpr ModInt operator -() const noexcept { return ModInt(-val_); }
	constexpr ModInt operator ++(int) noexcept { ModInt res = *this; ++*this; return res; }
	constexpr ModInt operator --(int) noexcept { ModInt res = *this; --*this; return res; }
	constexpr ModInt & operator ++() noexcept { val_ = val_ + 1 == M ? 0 : val_ + 1; return *this; }
	constexpr ModInt & operator --() noexcept { val_ = val_ == 0 ? M - 1 : val_ - 1; return *this; }
	constexpr ModInt & operator +=(const ModInt & rhs) noexcept { val_ += val_ < M - rhs.val_ ? rhs.val_ : rhs.val_ - M; return *this; }
	constexpr ModInt & operator -=(const ModInt & rhs) noexcept { val_ += val_ >= rhs.val_ ? -rhs.val_ : M - rhs.val_; return *this; }
	constexpr ModInt & operator *=(const ModInt & rhs) noexcept { val_ = static_cast<calc_type>(val_) * rhs.val_ % M; return *this; }
	constexpr ModInt & operator /=(const ModInt & rhs) noexcept { return *this *= rhs.inv(); }
	friend constexpr ModInt operator +(const ModInt & lhs, const ModInt & rhs) noexcept { return ModInt(lhs) += rhs; }
	friend constexpr ModInt operator -(const ModInt & lhs, const ModInt & rhs) noexcept { return ModInt(lhs) -= rhs; }
	friend constexpr ModInt operator *(const ModInt & lhs, const ModInt & rhs) noexcept { return ModInt(lhs) *= rhs; }
	friend constexpr ModInt operator /(const ModInt & lhs, const ModInt & rhs) noexcept { return ModInt(lhs) /= rhs; }
	friend constexpr bool operator ==(const ModInt & lhs, const ModInt & rhs) noexcept { return lhs.val_ == rhs.val_; }
	friend constexpr bool operator !=(const ModInt & lhs, const ModInt & rhs) noexcept { return !(lhs == rhs); }
	friend std::ostream & operator <<(std::ostream & os, const ModInt & rhs) { return os << rhs.val_; }
	friend std::istream & operator >>(std::istream & is, ModInt & rhs) { calc_type x; is >> x; rhs = ModInt(x); return is; }
	
	constexpr ModInt pow(calc_type n) const noexcept {
		ModInt res = 1, x = val_;
		if (n < 0) { x = x.inv(); n = -n; }
		while (n) { if (n & 1) res *= x; x *= x; n >>= 1; }
		return res;
	}
	
	constexpr ModInt inv() const noexcept {
		value_type a = val_, a1 = 1, a2 = 0, b = M, b1 = 0, b2 = 1;
		while (b > 0) {
			value_type q = a / b, r = a % b;
			value_type nb1 = a1 - q * b1, nb2 = a2 - q * b2;
			a = b; b = r;
			a1 = b1; b1 = nb1;
			a2 = b2; b2 = nb2;
		}
		assert(a == 1);
		return a1;
	}
};
using mint = ModInt<MOD>;

int main() {
	int N;
	cin >> N;
	vector<vector<int>> g(N);
	vector<int> indeg(N);
	REP(i, N - 1) {
		int A, B;
		scanf("%d %d", &A, &B);
		--A; --B;
		g[A].emplace_back(B);
		++indeg[B];
	}
	
	vector<int> depth(N), child(N);
	auto dfs = [&](auto && self, int u) -> int {
		child[u] = 1;
		for (int v : g[u]) {
			depth[v] = depth[u] + 1;
			child[u] += self(self, v);
		}
		return child[u];
	};
	const int root = find(ALL(indeg), 0) - indeg.begin();
	depth[root] = 1;
	dfs(dfs, root);
	
	mint ans = 0;
	REP(i, N) for (int v : g[i]) ans += (ll)depth[i] * child[v];
	cout << ans << endl;
}
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