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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#163714#6865. foreverlasting and fried-chickenjrjyy#WA 75ms3564kbC++204.0kb2023-09-04 14:28:112023-09-04 14:28:12

Judging History

你现在查看的是最新测评结果

  • [2023-09-04 14:28:12]
  • 评测
  • 测评结果:WA
  • 用时:75ms
  • 内存:3564kb
  • [2023-09-04 14:28:11]
  • 提交

answer

#include <bits/stdc++.h>

using i64 = long long;

template <typename T> constexpr T power(T a, i64 b) {
    T c{1}; for (; b; b /= 2, a *= a) if (b & 1) c *= a;
    return c;
}
template <int P> struct MInt {
    int x;
    constexpr MInt() : x{} {}
    constexpr MInt(i64 x_) : x{norm(x_ % getMod())} {}
    static int Mod;
    constexpr static int getMod() { return P > 0 ? P : Mod; }
    constexpr static void setMod(int Mod_) { Mod = Mod_; }
    constexpr int up(int x) const {
        if (x < 0) x += getMod();
        return x;
    }
    constexpr int down(int x) const {
        if (x >= getMod()) x -= getMod();
        return x;
    }
    constexpr int norm(int x) const {
        return up(down(x));
    }
    constexpr int val() const { return x; }
    explicit constexpr operator int() const { return x; }
    constexpr MInt operator-() const {
        MInt res; res.x = norm(getMod() - x); return res;
    }
    constexpr MInt inv() const {
        assert(x != 0);
        return power(*this, getMod() - 2);
    }
    constexpr MInt &operator+=(MInt rhs) & { return x = down(x + rhs.x), *this; }
    constexpr MInt &operator-=(MInt rhs) & { return x = up(x - rhs.x), *this; }
    constexpr MInt &operator*=(MInt rhs) & { return x = 1ll * x * rhs.x % getMod(), *this; }
    constexpr MInt &operator/=(MInt rhs) & { return *this *= rhs.inv(); }
    friend constexpr MInt operator+(MInt lhs, MInt rhs) { return lhs += rhs; }
    friend constexpr MInt operator-(MInt lhs, MInt rhs) { return lhs -= rhs; }
    friend constexpr MInt operator*(MInt lhs, MInt rhs) { return lhs *= rhs; }
    friend constexpr MInt operator/(MInt lhs, MInt rhs) { return lhs /= rhs; }
    friend constexpr bool operator==(MInt lhs, MInt rhs) { return lhs.val() == rhs.val(); }
    friend constexpr bool operator!=(MInt lhs, MInt rhs) { return lhs.val() != rhs.val(); }
    friend constexpr std::istream &operator>>(std::istream &is, MInt &a) {
        i64 x = 0; is >> x, a = MInt(x); return is;
    }
    friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a) {
        return os << a.val();
    }
};

template <int P> int MInt<P>::Mod = P;
template <> int MInt<0>::Mod = 1;
template <int V, int P> constexpr MInt<P> CInv = MInt<P>(V).inv();

constexpr int P = 1000000007;
using Z = MInt<P>;

struct Comb {
    int n; std::vector<Z> fac_, ifac_, inv_;
    Comb() : n(0), fac_{1}, ifac_{1}, inv_{0} {}
    Comb(int n) : Comb() { init(n); }
    void init(int m) {
        if (m <= n) return;
        fac_.resize(m + 1), ifac_.resize(m + 1), inv_.resize(m + 1);

        for (int i = n + 1; i <= m; ++i) fac_[i] = fac_[i - 1] * i;
        ifac_[m] = fac_[m].inv();
        for (int i = m; i > n + 1; --i) ifac_[i - 1] = ifac_[i] * i;
        for (int i = m; i > n; --i) inv_[i] = ifac_[i] * fac_[i - 1];
        n = m;
    }
    Z fac(int m) {
        if (n < m) init(2 * m);
        return fac_[m];
    }
    Z ifac(int m) {
        if (n < m) init(2 * m);
        return ifac_[m];
    }
    Z inv(int m) {
        if (n < m) init(2 * m);
        return inv_[m];
    }
    Z binom(int n, int m) {
        return n < m || m < 0 ? 0 : fac(n) * ifac(m) * ifac(n - m);
    }
} comb;

constexpr int N = 1000;

void solve() {
    int n, m;
    std::cin >> n >> m;

    std::vector<std::bitset<N>> adj(n);
    std::vector<int> f(n);
    for (int i = 0; i < m; ++i) {
        int u, v;
        std::cin >> u >> v;
        --u, --v;
        adj[u][v] = adj[v][u] = 1;
        f[u] += 1, f[v] += 1;
    }

    Z ans = 0;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            if (i != j) {
                int cnt = (adj[i] & adj[j]).count();
                ans += comb.binom(cnt, 4) * comb.binom(f[i] - 4, 2);
            }
        }
    }

    std::cout << ans << '\n';
}

int main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);

    int t;
    std::cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}

详细

Test #1:

score: 0
Wrong Answer
time: 75ms
memory: 3564kb

input:

9
8 10
1 2
1 3
1 4
1 5
1 6
1 7
8 4
8 5
8 6
8 7
10 12
1 2
1 3
1 4
1 5
1 6
1 7
8 4
8 5
8 6
8 7
8 9
8 10
11 13
1 2
1 3
1 4
1 5
1 6
1 7
8 4
8 5
8 6
8 7
8 9
8 10
1 11
11 14
1 2
1 3
1 4
1 5
1 6
1 7
8 4
8 5
8 6
8 7
8 9
8 10
1 11
1 8
10 45
5 10
2 9
5 8
3 10
2 10
4 9
4 3
4 2
5 6
7 1
10 6
10 7
6 1
8 3
5 1
7 5...

output:

1
2
4
9
63000
0
624414727
928162958
4088223

result:

wrong answer 4th lines differ - expected: '4', found: '9'