結果

問題 No.1333 Squared Sum
ユーザー haruki_Kharuki_K
提出日時 2021-01-09 07:32:43
言語 C++17
(gcc 13.2.0 + boost 1.83.0)
結果
AC  
実行時間 209 ms / 2,000 ms
コード長 8,628 bytes
コンパイル時間 4,687 ms
コンパイル使用メモリ 210,680 KB
実行使用メモリ 49,376 KB
最終ジャッジ日時 2023-08-10 21:34:45
合計ジャッジ時間 15,075 ms
ジャッジサーバーID
（参考情報） 		judge12 / 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
4,380 KB
testcase_01 AC 2 ms
4,380 KB
testcase_02 AC 1 ms
4,380 KB
testcase_03 AC 182 ms
17,892 KB
testcase_04 AC 167 ms
17,804 KB
testcase_05 AC 170 ms
17,956 KB
testcase_06 AC 178 ms
17,980 KB
testcase_07 AC 171 ms
17,876 KB
testcase_08 AC 160 ms
18,084 KB
testcase_09 AC 157 ms
17,904 KB
testcase_10 AC 163 ms
17,892 KB
testcase_11 AC 157 ms
17,892 KB
testcase_12 AC 149 ms
17,960 KB
testcase_13 AC 179 ms
49,372 KB
testcase_14 AC 178 ms
33,760 KB
testcase_15 AC 197 ms
45,364 KB
testcase_16 AC 1 ms
4,384 KB
testcase_17 AC 2 ms
4,380 KB
testcase_18 AC 1 ms
4,376 KB
testcase_19 AC 2 ms
4,380 KB
testcase_20 AC 2 ms
4,376 KB
testcase_21 AC 1 ms
4,384 KB
testcase_22 AC 2 ms
4,380 KB
testcase_23 AC 2 ms
4,380 KB
testcase_24 AC 1 ms
4,384 KB
testcase_25 AC 1 ms
4,384 KB
testcase_26 AC 204 ms
48,552 KB
testcase_27 AC 209 ms
34,504 KB
testcase_28 AC 209 ms
48,320 KB
testcase_29 AC 178 ms
49,376 KB
testcase_30 AC 53 ms
9,312 KB
testcase_31 AC 28 ms
6,664 KB
testcase_32 AC 79 ms
11,988 KB
testcase_33 AC 66 ms
10,112 KB
testcase_34 AC 142 ms
15,048 KB
testcase_35 AC 84 ms
11,920 KB
testcase_36 AC 46 ms
8,512 KB
testcase_37 AC 49 ms
8,520 KB
testcase_38 AC 54 ms
9,580 KB
testcase_39 AC 97 ms
13,204 KB
testcase_40 AC 116 ms
16,916 KB
testcase_41 AC 115 ms
17,024 KB
testcase_42 AC 130 ms
17,092 KB
testcase_43 AC 108 ms
17,328 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 # 

// >>> TEMPLATES
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
#define int ll
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define rep1(i,n) for (int i = 1; i <= (int)(n); i++)
#define repR(i,n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep1R(i,n) for (int i = (int)(n); i >= 1; i--)
#define loop(i,a,B) for (int i = a; i B; i++)
#define loopR(i,a,B) for (int i = a; i B; i--)
#define all(x) begin(x), end(x)
#define allR(x) rbegin(x), rend(x)
#define rng(x,l,r) begin(x) + (l), begin(x) + (r)
#define pb push_back
#define eb emplace_back
#define fst first
#define snd second
template <class A, class B> auto mp(A &&a, B &&b) { return make_pair(forward<A>(a), forward<B>(b)); }
template <class... T> auto mt(T&&... x) { return make_tuple(forward<T>(x)...); }
template <class Int> auto constexpr inf = numeric_limits<Int>::max()/2-1;
auto constexpr INF32 = inf<int32_t>;
auto constexpr INF64 = inf<int64_t>;
auto constexpr INF   = inf<int>;
#ifdef LOCAL
#include "debug.hpp"
#else
#define dump(...) (void)(0)
#define say(x) (void)(0)
#define debug if (0)
#endif
template <class T, class Comp> struct pque : priority_queue<T, vector<T>, Comp> {
    vector<T> &data() { return this->c; }
    void clear() { this->c.clear(); }
};
template <class T> using pque_max = pque<T, less<T>>;
template <class T> using pque_min = pque<T, greater<T>>;
template <class T, class = typename T::iterator, enable_if_t<!is_same<T, string>::value, int> = 0>
ostream& operator<<(ostream& os, T const& a) { bool f = true; for (auto const& x : a) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, size_t N, enable_if_t<!is_same<T, char>::value, int> = 0>
ostream& operator<<(ostream& os, const T (&a)[N]) { bool f = true; for (auto const& x : a) os << (f ? "" : " ") << x, f = false; return os; }
template <class T, class = decltype(begin(declval<T&>())), class = typename enable_if<!is_same<T, string>::value>::type>
istream& operator>>(istream& is, T &a) { for (auto& x : a) is >> x; return is; }
template <class T, class S> ostream& operator<<(ostream& os, pair<T, S> const& p) { return os << p.first << " " << p.second; }
template <class T, class S> istream& operator>>(istream& is, pair<T, S>& p) { return is >> p.first >> p.second; }
struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup;
template <class F> struct FixPoint : private F {
    constexpr FixPoint(F&& f) : F(forward<F>(f)) {}
    template <class... T> constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward<T>(x)...); }
};
struct MakeFixPoint { template <class F> constexpr auto operator|(F&& f) const { return FixPoint<F>(forward<F>(f)); } };
#define MFP MakeFixPoint()|
#define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__)
template <class T, size_t d> struct vec_impl {
    using type = vector<typename vec_impl<T,d-1>::type>;
    template <class... U> static type make_v(size_t n, U&&... x) { return type(n, vec_impl<T,d-1>::make_v(forward<U>(x)...)); }
};
template <class T> struct vec_impl<T,0> { using type = T; static type make_v(T const& x = {}) { return x; } };
template <class T, size_t d = 1> using vec = typename vec_impl<T,d>::type;
template <class T, size_t d = 1, class... Args> auto make_v(Args&&... args) { return vec_impl<T,d>::make_v(forward<Args>(args)...); }
template <class T> void quit(T const& x) { cout << x << endl; exit(0); }
template <class T, class U> constexpr bool chmin(T& x, U const& y) { if (x > y) { x = y; return true; } return false; }
template <class T, class U> constexpr bool chmax(T& x, U const& y) { if (x < y) { x = y; return true; } return false; }
template <class It> constexpr auto sumof(It b, It e) { return accumulate(b, e, typename iterator_traits<It>::value_type{}); }
template <class T> int sz(T const& x) { return x.size(); }
template <class C, class T> int lbd(C const& v, T const& x) { return lower_bound(begin(v), end(v), x)-begin(v); }
template <class C, class T> int ubd(C const& v, T const& x) { return upper_bound(begin(v), end(v), x)-begin(v); }
const int dx[] = { 1,0,-1,0,1,-1,-1,1 };
const int dy[] = { 0,1,0,-1,1,1,-1,-1 };
constexpr int popcnt(ll x) { return __builtin_popcountll(x); }
// [a,b]
template <class Int> Int rand(Int a, Int b) { static mt19937_64 mt{random_device{}()}; return uniform_int_distribution<Int>(a,b)(mt); }
i64 irand(i64 a, i64 b) { return rand<i64>(a,b); }
u64 urand(u64 a, u64 b) { return rand<u64>(a,b); }
template <class It> void shuffle(It l, It r) { shuffle(l, r, mt19937_64(random_device{}())); }
// <<<
// >>> modint

template <uint32_t md>
class modint {
    static_assert(md < (1u<<31), "");
    using M = modint;
    using i64 = int64_t;
    uint32_t x;
public:
    static constexpr uint32_t mod = md;
    constexpr modint(i64 x = 0) : x((x%=md) < 0 ? x+md : x) { }
    constexpr i64 val() const { return x; }
    constexpr explicit operator i64() const { return x; }
    constexpr bool operator==(M r) const { return x == r.x; }
    constexpr bool operator!=(M r) const { return x != r.x; }
    constexpr M operator+() const { return *this; }
    constexpr M operator-() const { return M()-*this; }
    constexpr M& operator+=(M r) { x += r.x; x = (x < md ? x : x-md); return *this; }
    constexpr M& operator-=(M r) { x += md-r.x; x = (x < md ? x : x-md); return *this; }
    constexpr M& operator*=(M r) { x = (uint64_t(x)*r.x)%md; return *this; }
    constexpr M& operator/=(M r) { return *this *= r.inv(); }
    constexpr M operator+(M r) const { return M(*this) += r; }
    constexpr M operator-(M r) const { return M(*this) -= r; }
    constexpr M operator*(M r) const { return M(*this) *= r; }
    constexpr M operator/(M r) const { return M(*this) /= r; }
    friend constexpr M operator+(i64 x, M y) { return M(x)+y; }
    friend constexpr M operator-(i64 x, M y) { return M(x)-y; }
    friend constexpr M operator*(i64 x, M y) { return M(x)*y; }
    friend constexpr M operator/(i64 x, M y) { return M(x)/y; }
    constexpr M inv() const { assert(x > 0); return pow(md-2); }
    constexpr M pow(i64 n) const {
        assert(not (x == 0 && n == 0));
        if (n < 0) return inv().pow(-n);
        M v = *this, r = 1;
        for (; n > 0; n >>= 1, v *= v) if (n&1) r *= v;
        return r;
    }
#ifdef LOCAL
    friend string to_s(M r) { return to_s(r.val(), mod); }
#endif
    friend ostream& operator<<(ostream& os, M r) { return os << r.val(); }
    friend istream& operator>>(istream& is, M &r) { i64 x; is >> x; r = x; return is; }
};

// <<<
//constexpr int64_t MOD = 998244353;
constexpr int64_t MOD = 1e9+7;
using mint = modint<MOD>;
mint sgn(int n) { return n%2 == 0 ? +1 : -1; }
// >>> mod table

template <uint32_t mod>
struct ModTable {
    vector<uint32_t> fact = {1,1}, finv = {1,1}, inv = {0,1};
    void calc(int n) {
        int old = fact.size();
        if (n < old) return;
        fact.resize(n+1);
        finv.resize(n+1);
        inv.resize(n+1);
        for (uint32_t i = old; i <= n; i++) {
            fact[i] = uint64_t(fact[i-1])*i % mod;
            inv[i] = mod - uint64_t(inv[mod%i])*(mod/i) % mod;
            finv[i] = uint64_t(finv[i-1])*inv[i] % mod;
        }
    }
};
ModTable<MOD> mod_tab;

modint<MOD> fact(int n) {
    assert(0 <= n);
    return mod_tab.calc(n), mod_tab.fact[n];
}
modint<MOD> finv(int n) {
    assert(0 <= n);
    return mod_tab.calc(n), mod_tab.finv[n];
}
modint<MOD> C(int n, int k) {
    if (n < 0 || k < 0 || n < k) return 0;
    return fact(n)*finv(k)*finv(n-k);
}
modint<MOD> P(int n, int k) {
    assert(k >= 0); assert(n >= k);
    return fact(n)*finv(n-k);
}

// <<<

int32_t main() {
    int n; cin >> n;
    struct edge { int to, cost; };
    vector<vector<edge>> g(n);
    rep (i, n-1) {
        int a, b; cin >> a >> b;
        --a, --b;
        int c; cin >> c;
        g[a].pb({b, c});
        g[b].pb({a, c});
    }

    mint ans = 0;
    using A = array<mint, 3>;
    def (dfs, int x, int p) -> A {
        A ret = { 1, 0, 0 };
        mint sum = 0;
        for (auto e : g[x]) {
            if (e.to == p) continue;
            auto s = dfs(e.to, x);
            s[2] = s[2] + 2*s[1]*e.cost + s[0]*e.cost*e.cost;
            s[1] = s[1] + s[0]*e.cost;
            s[0] = s[0];

            rep (i, 3) ret[i] += s[i];
            sum += s[2]*s[0] + s[1]*s[1];
        }
        mint val = ret[2]*ret[0] + ret[1]*ret[1] - sum;
        ans += val;
        return ret;
    };
    dfs(0, -1);
    cout << ans << endl;


}
0