結果
| 問題 | No.1833 Subway Planning |
| ユーザー |
👑  tute7627
|
| 提出日時 | 2022-02-04 22:15:32 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 598 ms / 4,000 ms |
| コード長 | 13,145 bytes |
| コンパイル時間 | 2,850 ms |
| コンパイル使用メモリ | 225,360 KB |
| 最終ジャッジ日時 | 2025-01-27 19:13:32 |
|
ジャッジサーバーID （参考情報） |
judge3 / judge4 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 23 |
ソースコード
//#define _GLIBCXX_DEBUG#include<bits/stdc++.h>using namespace std;#define endl '\n'#define lfs cout<<fixed<<setprecision(10)#define ALL(a) (a).begin(),(a).end()#define ALLR(a) (a).rbegin(),(a).rend()#define UNIQUE(a) (a).erase(unique((a).begin(),(a).end()),(a).end())#define spa << " " <<#define fi first#define se second#define MP make_pair#define MT make_tuple#define PB push_back#define EB emplace_back#define rep(i,n,m) for(ll i = (n); i < (ll)(m); i++)#define rrep(i,n,m) for(ll i = (ll)(m) - 1; i >= (ll)(n); i--)using ll = long long;using ld = long double;const ll MOD1 = 1e9+7;const ll MOD9 = 998244353;const ll INF = 1e18;using P = pair<ll, ll>;template<typename T> using PQ = priority_queue<T>;template<typename T> using QP = priority_queue<T,vector<T>,greater<T>>;template<typename T1, typename T2>bool chmin(T1 &a,T2 b){if(a>b){a=b;return true;}else return false;}template<typename T1, typename T2>bool chmax(T1 &a,T2 b){if(a<b){a=b;return true;}else return false;}ll median(ll a,ll b, ll c){return a+b+c-max({a,b,c})-min({a,b,c});}void ans1(bool x){if(x) cout<<"Yes"<<endl;else cout<<"No"<<endl;}void ans2(bool x){if(x) cout<<"YES"<<endl;else cout<<"NO"<<endl;}void ans3(bool x){if(x) cout<<"Yay!"<<endl;else cout<<":("<<endl;}template<typename T1,typename T2>void ans(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}template<typename T1,typename T2,typename T3>void anss(T1 x,T2 y,T3 z){ans(x!=y,x,z);};template<typename T>void debug(const T &v,ll h,ll w,string sv=" "){for(ll i=0;i<h;i++){cout<<v[i][0];for(ll j=1;j<w;j++)cout<<sv<<v[i][j];cout<<endl;}};template<typename T>void debug(const T &v,ll n,string sv=" "){if(n!=0)cout<<v[0];for(ll i=1;i<n;i++)cout<<sv<<v[i];cout<<endl;};template<typename T>void debug(const vector<T>&v){debug(v,v.size());}template<typename T>void debug(const vector<vector<T>>&v){for(auto &vv:v)debug(vv,vv.size());}template<typename T>void debug(stack<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}template<typename T>void debug(queue<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop();}cout<<endl;}template<typename T>void debug(deque<T> st){while(!st.empty()){cout<<st.front()<<" ";st.pop_front();}cout<<endl;}template<typename T>void debug(PQ<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}template<typename T>void debug(QP<T> st){while(!st.empty()){cout<<st.top()<<" ";st.pop();}cout<<endl;}template<typename T>void debug(const set<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}template<typename T>void debug(const multiset<T>&v){for(auto z:v)cout<<z<<" ";cout<<endl;}template<typename T,size_t size>void debug(const array<T, size> &a){for(auto z:a)cout<<z<<" ";cout<<endl;}template<typename T,typename V>void debug(const map<T,V>&v){for(auto z:v)cout<<"["<<z.first<<"]="<<z.second<<",";cout<<endl;}template<typename T>vector<vector<T>>vec(ll x, ll y, T w){vector<vector<T>>v(x,vector<T>(y,w));return v;}ll gcd(ll x,ll y){ll r;while(y!=0&&(r=x%y)!=0){x=y;y=r;}return y==0?x:y;}vector<ll>dx={1,-1,0,0,1,1,-1,-1};vector<ll>dy={0,0,1,-1,1,-1,1,-1};template<typename T>vector<T> make_v(size_t a,T b){return vector<T>(a,b);}template<typename... Ts>auto make_v(size_t a,Ts... ts){return vector<decltype(make_v(ts...))>(a,make_v(ts...));}template<typename T1, typename T2>ostream &operator<<(ostream &os, const pair<T1, T2>&p){return os << p.first << " " << p.second;}template<typename T>ostream &operator<<(ostream &os, const vector<T> &v){for(auto &z:v)os << z << " ";cout<<"|"; return os;}template<typename T>void rearrange(vector<int>&ord, vector<T>&v){auto tmp = v;for(int i=0;i<tmp.size();i++)v[i] = tmp[ord[i]];}template<typename Head, typename... Tail>void rearrange(vector<int>&ord,Head&& head, Tail&&... tail){rearrange(ord, head);rearrange(ord, tail...);}template<typename T> vector<int> ascend(const vector<T>&v){vector<int>ord(v.size());iota(ord.begin(),ord.end(),0);sort(ord.begin(),ord.end(),[&](int i,int j){return v[i]<v[j];});return ord;}template<typename T> vector<int> descend(const vector<T>&v){vector<int>ord(v.size());iota(ord.begin(),ord.end(),0);sort(ord.begin(),ord.end(),[&](int i,int j){return v[i]>v[j];});return ord;}template<typename T> vector<T> inv_perm(const vector<T>&ord){vector<T>inv(ord.size());for(int i=0;i<ord.size();i++)inv[ord[i]] = i;return inv;}ll FLOOR(ll n,ll div){assert(div>0);return n>=0?n/div:(n-div+1)/div;}ll CEIL(ll n,ll div){assert(div>0);return n>=0?(n+div-1)/div:n/div;}ll digitsum(ll n){ll ret=0;while(n){ret+=n%10;n/=10;}return ret;}ll modulo(ll n,ll d){return (n%d+d)%d;};template<typename T>T min(const vector<T>&v){return *min_element(v.begin(),v.end());}template<typename T>T max(const vector<T>&v){return *max_element(v.begin(),v.end());}template<typename T>T acc(const vector<T>&v){return accumulate(v.begin(),v.end(),T(0));};template<typename T>T reverse(const T &v){return T(v.rbegin(),v.rend());};//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());int popcount(ll x){return __builtin_popcountll(x);};int poplow(ll x){return __builtin_ctzll(x);};int pophigh(ll x){return 63 - __builtin_clzll(x);};template<typename T>T poll(queue<T> &q){auto ret=q.front();q.pop();return ret;};template<typename T>T poll(priority_queue<T> &q){auto ret=q.top();q.pop();return ret;};template<typename T>T poll(QP<T> &q){auto ret=q.top();q.pop();return ret;};template<typename T>T poll(stack<T> &s){auto ret=s.top();s.pop();return ret;};ll MULT(ll x,ll y){if(LLONG_MAX/x<=y)return LLONG_MAX;return x*y;}ll POW2(ll x, ll k){ll ret=1,mul=x;while(k){if(mul==LLONG_MAX)return LLONG_MAX;if(k&1)ret=MULT(ret,mul);mul=MULT(mul,mul);k>>=1;}return ret;}ll POW(ll x, ll k){ll ret=1;for(int i=0;i<k;i++){if(LLONG_MAX/x<=ret)return LLONG_MAX;ret*=x;}return ret;}template< typename T = int >struct edge {int to;T cost;int id;edge():id(-1){};edge(int to, T cost = 1, int id = -1):to(to), cost(cost), id(id){}operator int() const { return to; }};template<typename T>using Graph = vector<vector<edge<T>>>;template<typename T>Graph<T>revgraph(const Graph<T> &g){Graph<T>ret(g.size());for(int i=0;i<g.size();i++){for(auto e:g[i]){int to = e.to;e.to = i;ret[to].push_back(e);}}return ret;}template<typename T>Graph<T> readGraph(int n,int m,int indexed=1,bool directed=false,bool weighted=false){Graph<T> ret(n);for(int es = 0; es < m; es++){int u,v;T w=1;cin>>u>>v;u-=indexed,v-=indexed;if(weighted)cin>>w;ret[u].emplace_back(v,w,es);if(!directed)ret[v].emplace_back(u,w,es);}return ret;}template<typename T>Graph<T> readParent(int n,int indexed=1,bool directed=true){Graph<T>ret(n);for(int i=1;i<n;i++){int p;cin>>p;p-=indexed;ret[p].emplace_back(i);if(!directed)ret[i].emplace_back(p);}return ret;}template<typename T, typename F>struct DisjointSparseTable{int n;vector<vector<T>>data;const F func;DisjointSparseTable(vector<T>&v, const F &f):func(f),n(v.size()){int num=0;while((1<<num)<v.size())num++;data.assign(num+5,vector<T>(n+1, T()));if(n>=1)data[0][n-1]=v[n-1];for(int i=1;i<n;i++){int k = __builtin_ctz(i);data[k][i-1]=v[i-1];if(i!=n)data[k][i]=v[i];int l=i-(1<<k),r=min(n,i+(1<<k));for(int j=i-2;j>=l;j--)data[k][j]=func(v[j],data[k][j+1]);for(int j=i+1;j<r;j++)data[k][j]=func(data[k][j-1],v[j]);}}T query(int l,int r){//[l,r)r--;if(l==r)return data[0][l];ll k=31-__builtin_clz(l^r);return func(data[k][l],data[k][r]);}};template<typename T>struct HLD{using D=long long;int n;vector<int>sz;//部分木サイズvector<D>dep;vector<int>par;vector<int>head;Graph<T> &g;//隣接リストvector<edge<T>>edges;//データ構造に乗せるedge列vector<int>in,out;//[in,out)で部分木、[ina,inb]でa~bのパス(aが上)vector<int>comp;//連結成分の根//inは頂点のindexを表す。また、edge列の下側の頂点であるHLD(Graph<T> &g,int r=-1):g(g),n(g.size()){hld_build(r);}void hld_build(int root = -1){in.assign(n,-1);out.assign(n,-1);dep.assign(n,0);par.assign(n,-1);head.assign(n,-1);sz.assign(n,-1);comp.assign(n,-1);edges.assign(n,edge<T>());if(root == -1){//根がどこでも良い場合(森でも可)for(int i=0;i<n;i++){if(sz[i] == -1){head[i] = i;dfs_sz(i, 0, i);dfs_hld(i);}}}else{head[root] = root;dfs_sz(root, 0, root);dfs_hld(root);}}void dfs_sz(int k, D d,int r){sz[k] = 1;comp[k] = r;dep[k] = d;for(auto &e: g[k]){if(e.to == par[k])continue;par[e.to] = k;dfs_sz(e.to, d+e.cost, r);sz[k] += sz[e.to];if(sz[e.to] > sz[g[k][0].to])swap(e, g[k][0]);}}int time = 0;void dfs_hld(int k){in[k] = time++;for(auto e:g[k]){if(e.to == par[k])continue;head[e.to] = (e.to == g[k][0].to ? head[k]: e.to);edges[time] = e;dfs_hld(e.to);}out[k] = time;}int lca(int p,int q){while(1){if(in[p] < in[q])swap(p,q);if(head[p] == head[q])return q;p = par[head[p]];}}vector<pair<int,int>>query_path(int p,int q,bool isEdge){int r=lca(p,q);vector<pair<int,int>>ret;for(int i=0;i<2;i++){if(i == 1)swap(p,q);while(1){if(isEdge&&p==r)break;if(head[p]==head[r]){ret.emplace_back(in[r]+(isEdge?1:i),in[p]+1);break;}ret.emplace_back(in[head[p]],in[p]+1);p = par[head[p]];}}return ret;}vector<vector<pair<int,int>>>query_order_path(int p,int q,bool isEdge){//非可換クエリ用、配列0を順番を反転したデータ構造に、配列1を通常のデータ構造にvector<vector<pair<int,int>>>ret(2);int r=lca(p,q);for(int i=0;i<2;i++){if(i == 1)swap(p,q);while(1){if(isEdge&&p==r)break;if(head[p]==head[r]){if(i==0) ret[i].emplace_back(n-(in[p]+1),n-(in[r]+(isEdge?1:i)));else ret[i].emplace_back(in[r]+(isEdge?1:i),in[p]+1);break;}if(i==0) ret[i].emplace_back(n-(in[p]+1),n-(in[head[p]]));else ret[i].emplace_back(in[head[p]],in[p]+1);p = par[head[p]];}}reverse(ret[1].begin(), ret[1].end());return ret;}pair<int,int>query_subtree(int p,bool isEdge){return make_pair(in[p]+isEdge,out[p]);}//uのv方向の子 子孫関係は前もって確認すること(in,outを見る)int child(int u,int v){while(1){if(head[u]==head[v]){v=g[u][0].to;break;}v=head[v];if(par[v]==u)break;v=par[v];}return v;}//uをv方向に一つ進めた頂点int move(int u,int v){assert(u!=v);if(in[u]<in[v]&&in[v]<out[u])return child(u,v);else return par[u];}D dist(int u,int v){return dep[u]+dep[v]-2*dep[lca(u,v)];}vector<int>rev_in;int climb(int u,int k){if(rev_in.empty()){rev_in.resize(n);for(int i=0;i<n;i++)rev_in[in[i]]=i;}int nd=max<int>(dep[u]-k, 0);while(dep[u]>nd){if(dep[head[u]]>nd){u=par[head[u]];}else{u=rev_in[in[head[u]]+nd-dep[head[u]]];}}return u;}template<typename I>Graph<T>lca_tree(vector<I>&v){auto compare=[&](int x,int y){return in[x]<in[y];};sort(v.begin(),v.end(),compare);int sz1=v.size();for(int i=0;i<sz1-1;i++)v.push_back(lca(v[i],v[i+1]));sort(v.begin(),v.end(),compare);v.erase(unique(v.begin(),v.end()),v.end());int sz2=v.size();Graph<T>ret(sz2);stack<int>st;for(int i=0;i<sz2;i++){while(!st.empty()&&out[v[st.top()]]<=in[v[i]])st.pop();if(!st.empty())ret[st.top()].emplace_back(i,dep[v[i]]-dep[v[st.top()]]);st.push(i);}return ret;}};int main(){cin.tie(nullptr);ios_base::sync_with_stdio(false);ll res=0,buf=0;bool judge = true;ll n;cin>>n;Graph<ll>g(n);vector<ll>u(n-1),v(n-1),w(n);rep(i,0,n-1){cin>>u[i]>>v[i]>>w[i];u[i]--;v[i]--;g[u[i]].EB(v[i],w[i]);g[v[i]].EB(u[i],w[i]);}auto ord=descend(w);HLD hld(g);auto fmin=[&](ll x,ll y){return min(x,y);};vector<ll>dv(n);rep(i,1,n){dv[i]=hld.edges[i].cost;}DisjointSparseTable dst(dv,fmin);ll x=u[ord[0]],y=v[ord[0]];ll mi=w[ord[0]];res=w[ord[0]];//debug(dv);rep(i,0,n-1){chmin(res,max(w[ord[0]]-mi,w[ord[i+1]]));for(auto z:{u[ord[i+1]],v[ord[i+1]]}){ll p=hld.dist(x,y);ll q=hld.dist(y,z);ll r=hld.dist(x,z);if(p+q==r)y=z;else if(p+r==q)x=z;else if(q+r!=p)mi=-INF;auto tmp=hld.query_path(x,y,true);for(auto zz:tmp){chmin(mi,dst.query(zz.fi,zz.se));}}//cout<<ord[i] spa x spa y spa mi spa res<<endl;}cout<<res<<endl;return 0;}