Convert-Rooted-Tree(根付き木に変換) (graph/tree/convert-rooted-tree.hpp)

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• Last update: 2024-04-24 02:34:04+09:00
• Include: #include "graph/tree/convert-rooted-tree.hpp"

Depends on

• Graph Template(グラフテンプレート) (graph/graph-template.hpp)

Code

#pragma once

#include "../graph-template.hpp"

/**
 * @brief Convert-Rooted-Tree(根付き木に変換)
 */
template< typename T >
Graph< T > convert_rooted_tree(const Graph< T > &g, int r = 0) {
  int N = (int) g.size();
  Graph< T > rg(N);
  vector< int > v(N);
  v[r] = 1;
  queue< int > que;
  que.emplace(r);
  while(!que.empty()) {
    auto p = que.front();
    que.pop();
    for(auto &to : g[p]) {
      if(v[to] == 0) {
        v[to] = 1;
        que.emplace(to);
        rg.add_directed_edge(p, to, to.cost);
      }
    }
  }
  return rg;
}

#line 2 "graph/tree/convert-rooted-tree.hpp"

#line 2 "graph/graph-template.hpp"

/**
 * @brief Graph Template(グラフテンプレート)
 */
template< typename T = int >
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template< typename T = int >
struct Graph {
  vector< vector< Edge< T > > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  size_t size() const {
    return g.size();
  }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false, bool directed = false) {
    for(int i = 0; i < M; i++) {
      int a, b;
      cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if(weighted) cin >> c;
      if(directed) add_directed_edge(a, b, c);
      else add_edge(a, b, c);
    }
  }

  inline vector< Edge< T > > &operator[](const int &k) {
    return g[k];
  }

  inline const vector< Edge< T > > &operator[](const int &k) const {
    return g[k];
  }
};

template< typename T = int >
using Edges = vector< Edge< T > >;
#line 4 "graph/tree/convert-rooted-tree.hpp"

/**
 * @brief Convert-Rooted-Tree(根付き木に変換)
 */
template< typename T >
Graph< T > convert_rooted_tree(const Graph< T > &g, int r = 0) {
  int N = (int) g.size();
  Graph< T > rg(N);
  vector< int > v(N);
  v[r] = 1;
  queue< int > que;
  que.emplace(r);
  while(!que.empty()) {
    auto p = que.front();
    que.pop();
    for(auto &to : g[p]) {
      if(v[to] == 0) {
        v[to] = 1;
        que.emplace(to);
        rg.add_directed_edge(p, to, to.cost);
      }
    }
  }
  return rg;
}

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