結果

問題 No.1484 木に数を書き込む問題 / Just Write Numbers! 2
ユーザー warabi0906
提出日時 2023-02-10 13:08:55
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 178 ms / 2,000 ms
コード長 3,901 bytes
コンパイル時間 3,935 ms
コンパイル使用メモリ 242,644 KB
実行使用メモリ 29,768 KB
最終ジャッジ日時 2024-07-07 09:25:00
合計ジャッジ時間 8,763 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 29
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 #
プレゼンテーションモードにする

#include <bits/stdc++.h>
#include "atcoder/all"
#define debug cout << "OK" << endl;
template<typename T>
inline bool chmax(T& a, const T b) { if (a < b) { a = b; return true; } return false; }
template<typename T>
inline bool chmin(T& a, const T b) { if (a > b) { a = b; return true; } return false; }
inline int Code(char c) {
    if ('A' <= c and c <= 'Z')return (int)(c - 'A');
    if ('a' <= c and c <= 'z')return (int)(c - 'a');
    if ('0' <= c and c <= '9')return (int)(c - '0');
    assert(false);
}
using namespace std;
using namespace atcoder;
#define int long long
constexpr int MOD = 998244353;
constexpr int INF = (1LL << 63);
using minit = modint998244353;
template<typename T>
ostream& operator << (ostream& st, const vector<T>& v) {
    for (const T value : v) {
        st << value << " ";
    }
    return st;
}
template<typename T>
istream& operator >> (istream& st, vector<T>& v) {
    for (T& value : v) {
        st >> value;
    }
    return st;
}
struct edge {
    int to, cost;
};
//
class Tree {
private:
    int N;
    bool LCA_inited;
    vector<vector<edge>> G;
    vector<vector<int>> parent;
    vector<int> dist;
    vector<int> distC;
    void dfs(long long v, long long p, long long d, long long d2);
    void LCAinit();
    void D_dfs(int v, int p, int d);
public:
    Tree(int n);
    ~Tree();
    int max_dist;
    int s, t;
    vector<vector<edge>> Get_Graph();
    void add_edge(int u, int v, int c);
    void diameter();
    int lca(int u, int v);
    int get_dist(int u, int v);
    bool on_path(int u, int v, int a);
};
Tree::Tree(int N) {
    G.resize(N);
    LCA_inited = false;
    s = -1, t = -1, max_dist = -1;
    return;
}
Tree::~Tree() {}
vector<vector<edge>> Tree::Get_Graph() {
    return G;
}
void Tree::add_edge(int u, int v,int c) {
    G[v].push_back({ u,c });
    G[u].push_back({ v,c });
    return;
}
void Tree::LCAinit() {
    parent.assign(33, vector<long long>(N, -1LL));
    dist.assign(N, -1LL);
    distC.assign(N, -1LL);
    dfs(0LL, -1LL, 0LL, 0LL);
    for (int i = 0; i < 32; i++) {
        for (int j = 0; j < N; j++) {
            if (parent[i][j] < 0LL) {
                parent[i + 1][j] = -1LL;
            }
            else {
                parent[i + 1][j] = parent[i][parent[i][j]];
            }
        }
    }
    return;
}
void Tree::diameter() {
    D_dfs(0, -1, 0);
    s = t;
    D_dfs(s, -1, 0);
    return;
}
void Tree::D_dfs(int v, int p, int d) {
    if (max_dist < d) {
        max_dist = d;
        t = v;
    }
    for (const edge e : G[v]) {
        if (e.to == p)continue;
        D_dfs(e.to, v, d + e.cost);
    }
    return;
}
void Tree::dfs(int v, int p, int d, int d2) {
    parent[0][v] = p;
    dist[v] = d;
    distC[v] = d2;
    for (edge e : G[v]) {
        if (e.to == p)continue;
        dfs(e.to, v, d + 1, d2 + e.cost);
    }
    return;
}
int Tree::lca(int u, int v) {
    if (!LCA_inited)LCAinit(), LCA_inited = true;
    if (dist[u] < dist[v])swap(u, v);
    long long between = dist[u] - dist[v];
    for (int i = 0; i < 33; i++) {
        if (between & (1LL << i)) { u = parent[i][u]; }
    }
    if (u == v)return u;
    for (int i = 32; i >= 0; i--) {
        if (parent[i][u] != parent[i][v]) {
            u = parent[i][u];
            v = parent[i][v];
        }
    }
    assert(parent[0][u] == parent[0][v]);
    return parent[0][u];
}
int Tree::get_dist(int u, int v) {
    return distC[u] + distC[v] - 2 * distC[lca(u, v)];
}
bool Tree::on_path(int u, int v, int a) {
    return get_dist(u, v) == get_dist(u, a) + get_dist(v, a);
}
//
class Solver {
public:
    int T;
    Solver() :T(1) {}
    ~Solver(){}
    void multi();
    void solve() const;
    void sp(int x)const;
};
void Solver::multi() {
    cin >> T;
    return;
}
void Solver::sp(const int x)const {
    cout << fixed << setprecision(x) << endl;
    return;
}
void Solver::solve() const {
    int N;
    cin >> N;
    Tree tree(N);
    for (int i = 0; i < N - 1; i++) {
        int u, v;
        cin >> u >> v;
        u--; v--;
        tree.add_edge(u, v, 1);
    }
    tree.diameter();
    cout << 2 * (N - 1) - tree.max_dist << endl;
}
signed main() {
    Solver solver;
    //solver.multi();
    //solver.sp();
    for (int i = 0; i < solver.T; i++)
        solver.solve();
    return 0;
}
/*
* わらびのコードこーどすぺーす
 (σ･∀･)σｹﾞｯﾂ!!
*/
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