結果

問題 No.1103 Directed Length Sum
ユーザー finefine
提出日時 2020-07-03 21:48:19
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 485 ms / 3,000 ms
コード長 4,195 bytes
コンパイル時間 1,532 ms
コンパイル使用メモリ 176,416 KB
実行使用メモリ 155,648 KB
最終ジャッジ日時 2023-10-17 00:34:40
合計ジャッジ時間 7,094 ms
ジャッジサーバーID
(参考情報)
judge13 / judge12
このコードへのチャレンジ(β)

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
4,348 KB
testcase_01 AC 1 ms
4,348 KB
testcase_02 AC 313 ms
155,648 KB
testcase_03 AC 167 ms
50,184 KB
testcase_04 AC 231 ms
37,896 KB
testcase_05 AC 485 ms
60,876 KB
testcase_06 AC 145 ms
24,976 KB
testcase_07 AC 30 ms
8,656 KB
testcase_08 AC 51 ms
11,204 KB
testcase_09 AC 20 ms
6,708 KB
testcase_10 AC 72 ms
14,156 KB
testcase_11 AC 285 ms
40,192 KB
testcase_12 AC 145 ms
25,140 KB
testcase_13 AC 72 ms
14,656 KB
testcase_14 AC 15 ms
5,840 KB
testcase_15 AC 112 ms
20,528 KB
testcase_16 AC 318 ms
44,476 KB
testcase_17 AC 355 ms
46,808 KB
testcase_18 AC 69 ms
14,116 KB
testcase_19 AC 284 ms
41,544 KB
testcase_20 AC 24 ms
7,480 KB
testcase_21 AC 41 ms
10,656 KB
testcase_22 AC 219 ms
33,712 KB
testcase_23 AC 121 ms
21,592 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;

using ll = long long;

constexpr char newl = '\n';

using Graph = vector< vector<int> >;

bool dfs(int cur, vector<int>& memo, Graph& g, vector<int>& order) {
    memo[cur] = 1;
    for (int nex : g[cur]) {
        if (memo[nex] == 2) continue;
        if (memo[nex] == 1) return false;
        if (!dfs(nex, memo, g, order)) return false;
    }
    memo[cur] = 2;
    order.push_back(cur);
    return true;
}

bool tsort(Graph& g, vector<int>& order) {
    vector<int> memo(g.size(), 0);
    for (int i = 0; i < g.size(); i++) {
        if (memo[i] != 0) continue;
        if (!dfs(i, memo, g, order)) return false;
    }
    // reverse(order.begin(), order.end());
    return true;
}

// https://noshi91.hatenablog.com/entry/2019/03/31/174006
template <std::uint_fast64_t Modulus>
struct ModInt {
    using u64 = std::uint_fast64_t;

    static constexpr u64 MOD = Modulus;

    u64 val;

    constexpr ModInt(const u64 x = 0) noexcept : val(x % MOD) {}

    constexpr ModInt operator+() const noexcept { return ModInt(*this); }
    constexpr ModInt operator-() const noexcept {
        ModInt res(*this);
        if (res.val != 0) res.val = MOD - res.val;
        return res;
    }

    constexpr bool operator==(const ModInt& rhs) const noexcept { return val == rhs.val; }
    constexpr bool operator!=(const ModInt& rhs) const noexcept { return val != rhs.val; }

    // prefix increment/decrement
    constexpr ModInt& operator++() noexcept { return *this += ModInt(1); }
    constexpr ModInt& operator--() noexcept { return *this -= ModInt(1); }

    // postfix increment/decrement
    constexpr ModInt operator++(int) noexcept {
        ModInt tmp(*this);
        ++*this;
        return tmp;
    }
    constexpr ModInt operator--(int) noexcept {
        ModInt tmp(*this);
        --*this;
        return tmp;
    }

    constexpr ModInt operator+(const ModInt& rhs) const noexcept {
        return ModInt(*this) += rhs;
    }
    constexpr ModInt operator-(const ModInt& rhs) const noexcept {
        return ModInt(*this) -= rhs;
    }
    constexpr ModInt operator*(const ModInt& rhs) const noexcept {
        return ModInt(*this) *= rhs;
    }
    constexpr ModInt operator/(const ModInt& rhs) const noexcept {
        return ModInt(*this) /= rhs;
    }

    constexpr ModInt& operator+=(const ModInt& rhs) noexcept {
        val += rhs.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr ModInt& operator-=(const ModInt& rhs) noexcept {
        if (val < rhs.val) val += MOD;
        val -= rhs.val;
        return *this;
    }
    constexpr ModInt& operator*=(const ModInt& rhs) noexcept {
        val = val * rhs.val % MOD;
        return *this;
    }

    // prime Modulus only
    constexpr ModInt& operator/=(const ModInt& rhs) noexcept {
        return *this *= rhs.inv();
    }

    // prime Modulus only
    constexpr ModInt inv() const noexcept {
        return pow(*this, MOD - 2);
    }
};

template<std::uint_fast64_t Modulus>
constexpr ModInt<Modulus> pow(ModInt<Modulus> x, std::uint_fast64_t n) {
    ModInt<Modulus> res(1);
    while (n) {
        if (n & 1) res *= x;
        x *= x;
        n >>= 1;
    }
    return res;
}

template<std::uint_fast64_t Modulus>
istream& operator>>(istream& is, ModInt<Modulus>& x) {
    std::uint_fast64_t val;
    is >> val;
    x = ModInt<Modulus>(val);
    return is;
}

template<std::uint_fast64_t Modulus>
ostream& operator<<(ostream& os, const ModInt<Modulus>& x) {
    return os << x.val;
}

using mint = ModInt<1000000007>;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    Graph g(n);
    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        --a; --b;

        g[a].push_back(b);
    }

    vector<int> order;
    tsort(g, order);

    vector<mint> sum(n, 0), cnt(n, 0);
    mint ans = 0;
    for (int i : order) {
        for (int j : g[i]) {
            cnt[i] += cnt[j] + 1;
            sum[i] += sum[j] + cnt[j] + 1;
        }
        // cerr << i << ": " << sum[i] << " " << cnt[i] << newl;
        ans += sum[i];
    }
    cout << ans << newl;

    return 0;
}
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