結果
| 問題 | No.1333 Squared Sum |
| ユーザー |
 heno239
|
| 提出日時 | 2021-01-08 21:52:23 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 500 ms / 2,000 ms |
| コード長 | 5,028 bytes |
| コンパイル時間 | 1,987 ms |
| コンパイル使用メモリ | 151,408 KB |
| 最終ジャッジ日時 | 2025-01-17 11:50:14 |
|
ジャッジサーバーID （参考情報） |
judge5 / judge1 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| other | AC * 44 |
ソースコード
#pragma GCC optimize("Ofast")//#pragma GCC target ("sse4")#include<iostream>#include<string>#include<cstdio>#include<vector>#include<cmath>#include<algorithm>#include<functional>#include<iomanip>#include<queue>#include<ciso646>#include<random>#include<map>#include<set>#include<bitset>#include<stack>#include<unordered_map>#include<unordered_set>#include<utility>#include<cassert>#include<complex>#include<numeric>#include<array>using namespace std;//#define int long longtypedef long long ll;typedef unsigned long long ul;typedef unsigned int ui;constexpr ll mod = 1000000007;const ll INF = mod * mod;typedef pair<int, int>P;#define stop char nyaa;cin>>nyaa;#define rep(i,n) for(int i=0;i<n;i++)#define per(i,n) for(int i=n-1;i>=0;i--)#define Rep(i,sta,n) for(int i=sta;i<n;i++)#define rep1(i,n) for(int i=1;i<=n;i++)#define per1(i,n) for(int i=n;i>=1;i--)#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)#define all(v) (v).begin(),(v).end()typedef pair<ll, ll> LP;typedef double ld;typedef pair<ld, ld> LDP;const ld eps = 1e-12;const ld pi = acosl(-1.0);ll mod_pow(ll x, ll n, ll m = mod) {if (n < 0) {ll res = mod_pow(x, -n, m);return mod_pow(res, m - 2, m);}if (abs(x) >= m)x %= m;if (x < 0)x += m;ll res = 1;while (n) {if (n & 1)res = res * x % m;x = x * x % m; n >>= 1;}return res;}struct modint {ll n;modint() :n(0) { ; }modint(ll m) :n(m) {if (n >= mod)n %= mod;else if (n < 0)n = (n % mod + mod) % mod;}operator int() { return n; }};bool operator==(modint a, modint b) { return a.n == b.n; }modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }modint operator+(modint a, modint b) { return a += b; }modint operator-(modint a, modint b) { return a -= b; }modint operator*(modint a, modint b) { return a *= b; }modint operator^(modint a, ll n) {if (n == 0)return modint(1);modint res = (a * a) ^ (n / 2);if (n % 2)res = res * a;return res;}ll inv(ll a, ll p) {return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);}modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }modint operator/=(modint& a, modint b) { a = a / b; return a; }const int max_n = 1 << 17;modint fact[max_n], factinv[max_n];void init_f() {fact[0] = modint(1);for (int i = 0; i < max_n - 1; i++) {fact[i + 1] = fact[i] * modint(i + 1);}factinv[max_n - 1] = modint(1) / fact[max_n - 1];for (int i = max_n - 2; i >= 0; i--) {factinv[i] = factinv[i + 1] * modint(i + 1);}}modint comb(int a, int b) {if (a < 0 || b < 0 || a < b)return 0;return fact[a] * factinv[b] * factinv[a - b];}modint combP(int a, int b) {if (a < 0 || b < 0 || a < b)return 0;return fact[a] * factinv[a - b];}using mP = pair<modint, modint>;const int mn = 1 << 18;struct edge {int to; ll cost;};using Data = array<modint,3>;vector<edge> G[mn];vector<int> ids[mn];vector<Data> memo[mn];vector<ll> costs[mn];int root;Data merge(Data a, Data b) {Data res;//res[0] = a[0] + b[0];res[1] = a[1] + b[1];res[2] = a[2] + b[2];//return res;}Data dfs(int id, int fr) {Data res;////initializeres = {1, 0,0 };//for (edge e : G[id]) {if (e.to == fr)continue;Data nex = dfs(e.to, id);////update with edgenex[2]+= nex[0]*(modint)(e.cost*e.cost) + (modint)(2*e.cost)* nex[1];nex[1] += (modint)e.cost * nex[0];//res = merge(res, nex);ids[id].push_back(e.to);memo[id].push_back(nex);costs[id].push_back(e.cost);}////update for return//return res;}modint ans = 0;void invdfs(int id, int fr, Data pre) {vector<Data> v;for (Data d : memo[id])v.push_back(d);if (fr >= 0)v.push_back(pre);int len = v.size();////calcurate id's ansData ex = { 0,0,0 };for (Data d : v)ex = merge(ex, d);ans += ex[2];//cout << id << " " << ex[0]<<" "<<ex[1]<<" "<<ex[2] << "\n";//vector<Data> le(len + 1);vector<Data> ri(len + 1);//Data init_c = { 0,0,0 };//le[0] = init_c;rep(i, len) {le[i + 1] = merge(le[i], v[i]);}ri[len] = init_c;per(i, len) {ri[i] = merge(ri[i + 1], v[i]);}rep(i, ids[id].size()) {int to = ids[id][i];Data d = merge(le[i], ri[i + 1]);////update for returnd[0] += 1;d[2] += (modint)(costs[id][i]*costs[id][i])*d[0]+(modint)(2*costs[id][i]) * d[1];d[1] += (modint)costs[id][i]*d[0];//invdfs(to, id, d);}}void yaru() {dfs(root, -1);invdfs(root, -1, { 0,0 });}void solve() {int n; cin >> n;rep(i, n - 1) {int a, b, c; cin >> a >> b >> c; a--; b--;G[a].push_back({ b,c });G[b].push_back({ a,c });}yaru();ans = ans / (modint)2;cout << ans << "\n";}signed main() {ios::sync_with_stdio(false);cin.tie(0);//cout << fixed << setprecision(15);//init_f();//init();//expr();//int t; cin >> t; rep(i, t)solve();return 0;}