結果
| 問題 | No.1333 Squared Sum |
| ユーザー |
 noya2
|
| 提出日時 | 2022-11-03 04:17:34 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 423 ms / 2,000 ms |
| コード長 | 6,326 bytes |
| コンパイル時間 | 4,674 ms |
| コンパイル使用メモリ | 271,968 KB |
| 最終ジャッジ日時 | 2025-02-08 16:56:32 |
|
ジャッジサーバーID （参考情報） |
judge2 / judge2 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| other | AC * 44 |
ソースコード
#line 1 "c.cpp"#include<bits/stdc++.h>#include<atcoder/all>#define rep(i,n) for (int i = 0; i < int(n); ++i)#define repp(i,n,m) for (int i = m; i < int(n); ++i)#define reb(i,n) for (int i = int(n)-1; i >= 0; --i)#define all(v) v.begin(),v.end()using namespace std;using namespace atcoder;using ll = long long;using ull = unsigned long long;using ld = long double;using P = pair<int, int>;using PL = pair<long long, long long>;using pdd = pair<long double, long double>;using pil = pair<int,ll>;using pli = pair<ll,int>;template<class T>istream &operator>>(istream &is,vector<T> &v){for(auto &e:v)is>>e;return is;}template<typename T>bool range(T a,T b,T x){return (a<=x&&x<b);}template<typename T>bool rrange(T a,T b,T c,T d,T x,T y){return (range(a,c,x)&&range(b,d,y));}template<typename T>void rev(vector<T> &v){reverse(v.begin(),v.end());}void revs(string &s) {reverse(s.begin(),s.end());}template<typename T>void sor(vector<T> &v, int f=0){sort(v.begin(),v.end());if(f!=0) rev(v);}template<typename T>bool chmin(T &a,const T &b){if(a>b){a=b;return true;}return false;}template<typename T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}template<typename T>void uniq(vector<T> &v){sor(v);v.erase(unique(v.begin(),v.end()),v.end());}template<typename T1, typename T2>void print(pair<T1,T2> a);template<typename T>void print(vector<T> v);template<typename T>void print(vector<vector<T>> v);void print(){ putchar(' '); }void print(bool a){ printf("%d", a); }void print(int a){ printf("%d", a); }void print(long a){ printf("%ld", a); }void print(long long a){ printf("%lld", a); }void print(char a){ printf("%c", a); }void print(char a[]){ printf("%s", a); }void print(const char a[]){ printf("%s", a); }void print(long double a){ printf("%.15Lf", a); }void print(const string& a){ for(auto&& i : a) print(i); }void print(unsigned int a){ printf("%u", a); }void print(unsigned long long a) { printf("%llu", a); }template<class T> void print(const T& a){ cout << a; }int out(){ putchar('\n'); return 0; }template<class T> int out(const T& t){ print(t); putchar('\n'); return 0; }template<class Head, class... Tail> int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; }template<typename T1,typename T2>void print(pair<T1,T2> a){print(a.first);print(),print(a.second);}template<typename T>void print(vector<T> v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())print();}}template<typename T>void print(vector<vector<T>> v){for(auto ite=v.begin();ite!=v.end();){print(*ite);if(++ite!=v.end())out();}}void yes(){out("Yes");}void no (){out("No");}void yn (bool t){if(t)yes();else no();}void fast_io(){cin.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(20);}void o(){out("!?");}namespace noya2{const int INF = 1001001007;const long long mod1 = 998244353;const long long mod2 = 1000000007;const long long inf = 2e18;const long double pi = 3.14159265358979323;const long double eps = 1e-7;const vector<int> dx = {0,1,0,-1,1,1,-1,-1};const vector<int> dy = {1,0,-1,0,1,-1,-1,1};const string ALP = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";const string alp = "abcdefghijklmnopqrstuvwxyz";const string NUM = "0123456789";} // namespace noya2using namespace noya2;using mint = modint1000000007;void out(mint a){out(a.val());}void out(vector<mint> a){vector<ll> b(a.size()); rep(i,a.size()) b[i] = a[i].val(); out(b);}void out(vector<vector<mint>> a){for (auto v : a) out(v);}istream &operator>>(istream &is,vector<mint> &v){for(auto &e:v){ll _x;is>>_x;e=_x;}return is;}#line 2 "Rerooting.hpp"#line 4 "Rerooting.hpp"namespace noya2 {using namespace std;template<class E, class V, E (*merge)(E, E), E (*e)(), E (*put_edge)(V, int), V (*put_vertex)(E, int)>struct Rerooting {struct edge{int from, to, idx, rev_idx;};Rerooting (int _n = 0) : n(_n) { es.resize(n);}void add_edge(int u, int v, int idx1, int idx2){es[u].push_back({u,v,idx1,idx2});es[v].push_back({v,u,idx2,idx1});}V build(int v = 0){root = v;vis.resize(n,0);outs.resize(n);return dfs(root);}vector<V> reroot(){reverse_edge.resize(n);reverse_edge[root] = e();answers.resize(n);bfs(root);return answers;}private:int n, root;vector<vector<edge>> es;vector<int> vis;vector<vector<E>> outs;vector<E> reverse_edge;vector<V> answers;V dfs(int v){vis[v]++;E val = e();for (auto &p : es[v]){if (vis[p.to] > 0 && p.to != es[v].back().to) swap(p,es[v].back());if (vis[p.to] > 0) continue;E nval = put_edge(dfs(p.to),p.idx);outs[v].emplace_back(nval);val = merge(val,nval);}return put_vertex(val,v);}void bfs(int v){int siz = outs[v].size();vector<E> lui(siz+1), rui(siz+1);lui[0] = e(), rui[siz] = e();for (int i = 0; i < siz; i++) lui[i+1] = merge(lui[i],outs[v][i]);for (int i = siz-1; i >= 0; i--) rui[i] = merge(outs[v][i],rui[i+1]);for (int i = 0; i < siz; i++){reverse_edge[es[v][i].to] = put_edge(put_vertex(merge(merge(lui[i],rui[i+1]),reverse_edge[v]),v),es[v][i].rev_idx);bfs(es[v][i].to);}answers[v] = put_vertex(merge(lui[siz],reverse_edge[v]), v);}};} // namespace noya2#line 78 "c.cpp"vector<mint> a;struct S{mint s, s2, siz;};S op(S a, S b){S c;c.siz = a.siz + b.siz;c.s = a.s + b.s;c.s2 = a.s2 + b.s2;return c;}S e(){return S{0,0,0};}S pute(S x, int i){S y;y.siz = x.siz;y.s = x.s + a[i] * x.siz;y.s2 = x.s2 + 2 * a[i] * x.s + a[i] * a[i] * x.siz;return y;}S putv(S x, int v){x.siz += 1;return x;}void solve(){int n; cin >> n;a.resize(n-1);Rerooting<S,S,op,e,pute,putv> g(n);rep(i,n-1){int u, v; cin >> u >> v;ll c; cin >> c; a[i] = c;g.add_edge(u-1,v-1,i,i);}g.build();mint ans = 0;for (auto x : g.reroot()) ans += x.s2;ans /= 2;out(ans.val());}int main(){fast_io();int t = 1; //cin >> t;while(t--) solve();}