結果
| 問題 | No.1333 Squared Sum |
| ユーザー |
 minato
|
| 提出日時 | 2021-01-09 03:09:39 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 252 ms / 2,000 ms |
| コード長 | 9,544 bytes |
| コンパイル時間 | 2,446 ms |
| コンパイル使用メモリ | 210,712 KB |
| 最終ジャッジ日時 | 2025-01-17 15:02:58 |
|
ジャッジサーバーID （参考情報） |
judge4 / judge3 |
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| ファイルパターン | 結果 |
|---|---|
| other | AC * 44 |
ソースコード
#include <bits/stdc++.h>using namespace std;using ll = long long;using ull = unsigned long long;using i128 = __int128_t;using pii = pair<int, int>;using pll = pair<long long, long long>;template<class T> using vec = vector<T>;template<class T> using vvec = vector<vector<T>>;#define rep(i, n) for (int i = 0; i < (n); i++)#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)#define all(x) (x).begin(), (x).end()constexpr char ln = '\n';istream& operator>>(istream& is, __int128_t& x) {x = 0;string s;is >> s;int n = int(s.size()), it = 0;if (s[0] == '-') it++;for (; it < n; it++) x = (x * 10 + s[it] - '0');if (s[0] == '-') x = -x;return is;}ostream& operator<<(ostream& os, __int128_t x) {if (x == 0) return os << 0;if (x < 0) os << '-', x = -x;deque<int> deq;while (x) deq.emplace_front(x % 10), x /= 10;for (int e : deq) os << e;return os;}template<class T1, class T2>ostream& operator<<(ostream& os, const pair<T1, T2>& p) {return os << "(" << p.first << ", " << p.second << ")";}template<class T>ostream& operator<<(ostream& os, const vector<T>& v) {os << "{";for (int i = 0; i < int(v.size()); i++) {if (i) os << ", ";os << v[i];}return os << "}";}template<class Container> inline int SZ(Container& v) { return int(v.size()); }template<class T> inline void UNIQUE(vector<T>& v) { v.erase(unique(v.begin(), v.end()), v.end()); }template<class T1, class T2> inline bool chmax(T1& a, T2 b) { if (a < b) {a = b; return true ;} return false ;}template<class T1, class T2> inline bool chmin(T1& a, T2 b) { if (a > b) {a = b; return true ;} return false ;}inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); }inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); }inline int popcount(ull x) { return __builtin_popcountll(x); }inline int kthbit(ull x, int k) { return (x>>k) & 1; }inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x-1) * 10; }inline void print() { cout << "\n"; }template<class T>inline void print(const vector<T>& v) {for (int i = 0; i < int(v.size()); i++) {if (i) cout << " ";cout << v[i];}print();}template<class T, class... Args>inline void print(const T& x, const Args& ... args) {cout << x << " ";print(args...);}#ifdef MINATO_LOCALinline void debug_out() { cerr << endl; }template <class T, class... Args>inline void debug_out(const T& x, const Args& ... args) {cerr << " " << x;debug_out(args...);}#define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__)#define dump(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl#else#define debug(...) (void(0))#define dump(x) (void(0))#endifstruct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////template<int m>struct ModInt {public:static constexpr int mod() { return m; }static ModInt raw(int v) {ModInt x;x._v = v;return x;}ModInt() : _v(0) {}ModInt(long long v) {long long x = (long long)(v % (long long)(umod()));if (x < 0) x += umod();_v = (unsigned int)(x);}unsigned int val() const { return _v; }ModInt& operator++() {_v++;if (_v == umod()) _v = 0;return *this;}ModInt& operator--() {if (_v == 0) _v = umod();_v--;return *this;}ModInt operator++(int) {ModInt result = *this;++*this;return result;}ModInt operator--(int) {ModInt result = *this;--*this;return result;}ModInt& operator+=(const ModInt& rhs) {_v += rhs._v;if (_v >= umod()) _v -= umod();return *this;}ModInt& operator-=(const ModInt& rhs) {_v -= rhs._v;if (_v >= umod()) _v += umod();return *this;}ModInt& operator*=(const ModInt& rhs) {unsigned long long z = _v;z *= rhs._v;_v = (unsigned int)(z % umod());return *this;}ModInt& operator^=(long long n) {ModInt x = *this;*this = 1;if (n < 0) x = x.inv(), n = -n;while (n) {if (n & 1) *this *= x;x *= x;n >>= 1;}return *this;}ModInt& operator/=(const ModInt& rhs) { return *this = *this * rhs.inv(); }ModInt operator+() const { return *this; }ModInt operator-() const { return ModInt() - *this; }ModInt pow(long long n) const {ModInt r = *this;r ^= n;return r;}ModInt inv() const {int a = _v, b = umod(), y = 1, z = 0, t;for (; ; ) {t = a / b; a -= t * b;if (a == 0) {assert(b == 1 || b == -1);return ModInt(b * z);}y -= t * z;t = b / a; b -= t * a;if (b == 0) {assert(a == 1 || a == -1);return ModInt(a * y);}z -= t * y;}}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 ModInt operator^(const ModInt& lhs, long long rhs) { return ModInt(lhs) ^= rhs; }friend bool operator==(const ModInt& lhs, const ModInt& rhs) { return lhs._v == rhs._v; }friend bool operator!=(const ModInt& lhs, const ModInt& rhs) { return lhs._v != rhs._v; }friend ModInt operator+(long long lhs, const ModInt& rhs) { return (ModInt(lhs) += rhs); }friend ModInt operator-(long long lhs, const ModInt& rhs) { return (ModInt(lhs) -= rhs); }friend ModInt operator*(long long lhs, const ModInt& rhs) { return (ModInt(lhs) *= rhs); }friend ostream& operator<<(ostream& os, const ModInt& M) { return os << M._v; }friend istream& operator>>(istream& is, ModInt& M) {long long x; is >> x;M = ModInt(x);return is;}private:unsigned int _v;static constexpr unsigned int umod() { return m; }};constexpr int MOD = 1000000007;//constexpr int MOD = 998244353;using mint = ModInt<MOD>;struct ModCombination {private:int max_n;vector<mint> fac_,facinv_;public:ModCombination() {}ModCombination(int n) : max_n(n), fac_(n+1), facinv_(n+1) {assert(1 <= n);fac_[0] = 1;for (int i = 1; i <= n; i++) fac_[i] = fac_[i-1]*i;facinv_[n] = fac_[n].inv();for (int i = n; i >= 1; i--) facinv_[i-1] = facinv_[i]*i;}mint fac(int k) const {assert(0 <= k and k <= max_n);return fac_[k];}mint facinv(int k) const {assert(0 <= k and k <= max_n);return facinv_[k];}mint invs(int k) const {assert(1 <= k and k <= max_n);return facinv_[k]*fac_[k-1];}mint P(int n, int k) const {if (k < 0 or k > n) return mint(0);assert(n <= max_n);return fac_[n]*facinv_[n-k];}mint C(int n, int k) const {if (k < 0 or k > n) return mint(0);assert(n <= max_n);return fac_[n]*facinv_[n-k]*facinv_[k];}mint H(int n, int k) const {if (n == 0 and k == 0) return mint(1);return C(n+k-1,k);}mint catalan(int n) const {if (n == 0) return mint(1);return C(n*2,n) - C(n*2,n-1);}};template<typename T>struct edge {int src,to;T cost;int id;edge(){}edge(int to, T cost) : src(-1), to(to), cost(cost), id(-1) {}edge(int src, int to, T cost) : src(src), to(to), cost(cost), id(-1) {}edge(int src, int to, T cost, int id) : src(src), to(to), cost(cost), id(id) {}};int main() {int N; cin >> N;vvec<edge<mint>> G(N);rep(i,N-1) {int u,v,w; cin >> u >> v >> w;u--; v--;G[u].emplace_back(v,w);G[v].emplace_back(u,w);}vec<int> sub(N,1);vec<mint> dp1(N),dp2(N);{auto dfs=[&](auto self, int v, int pv)->void {for (auto& e : G[v]) {if (e.to==pv) continue;dp2[e.to] = dp2[v]+e.cost;self(self,e.to,v);sub[v] += sub[e.to];dp1[v] += dp1[e.to]+e.cost*sub[e.to];}return;};dfs(dfs,0,-1);}vec<mint> dp(N);rep(i,N) dp[0] += dp2[i]*dp2[i];{auto dfs=[&](auto self, int v, int pv, mint val)->void {debug(val);for (auto& e : G[v]) {if (e.to==pv) continue;dp[e.to] = dp[v] + e.cost*e.cost*N + e.cost*2*(val-(dp1[e.to]+e.cost*sub[e.to])*2);self(self,e.to,v,dp1[e.to] + (val - (dp1[e.to]+e.cost*sub[e.to]) + e.cost*(N-sub[e.to])));}return;};dfs(dfs,0,-1,dp1[0]);}debug(dp);mint ans = accumulate(all(dp),mint(0));ans /= 2;cout << ans << ln;}