ctci/common_graphs_trees.cpp at master · sbashett/ctci · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
#include "common_header.hpp"
#include <iostream>
#include <map>
#include <queue>
#include <vector>

using namespace std;

namespace myspace {

GraphNode::GraphNode() : visited(false), id(-1), parent(NULL) {}
GraphNode::GraphNode(int id) : visited(false), id(id), parent(NULL) {}
GraphNode::GraphNode(string name) : name(name), visited(false), parent(NULL) {}

void createGraph_manual(Graph &graph, vector<vector<int>> &edges) {
  map<int, GraphNode *>::iterator find_iterator_parent, find_iterator_child;

  for (auto &edge : edges) {
    find_iterator_parent = graph.map_nodes.find(edge.at(0));
    if (find_iterator_parent == graph.map_nodes.end()) { // new vertex
      graph.map_nodes.insert(make_pair(edge.at(0), new GraphNode(edge[0])));
      find_iterator_parent = graph.map_nodes.find(edge.at(0));
    }

    find_iterator_child = graph.map_nodes.find(edge.at(1));
    if (find_iterator_child == graph.map_nodes.end()) { // new vertex
      graph.map_nodes.insert(make_pair(edge.at(1), new GraphNode(edge[1])));
      find_iterator_child = graph.map_nodes.find(edge.at(1));
    }

    find_iterator_parent->second->adj.push_back(find_iterator_child->second);
    // if(find_iterator_child->parent==NULL)
  }
}

void Graph::print_graph() {
  cout << "adjacency list of graph:\n";

  for (auto n : this->map_nodes) { // iterate over each pair object in map

    cout << n.second->id << ": ";
    for (auto ptr_adj_nodes : n.second->adj) {
      cout << ptr_adj_nodes->id << ' ';
    }
    cout << '\n';
  }
}

void Graph::clear_graph() {
  for (auto n : this->map_nodes) {
    n.second->adj.clear();
    delete n.second;
  }
  map_nodes.clear();
}

void Graph::reset_visited_flags() {
  for (auto n : this->map_nodes)
    n.second->visited = false;
}

bool depthSearch(GraphNode *ptr_source_node, int des_id, SingleLL *&path_seq) {

  bool pathExist = false;

  for (auto ptr_adj_nodes : ptr_source_node->adj) {
    if (ptr_adj_nodes->visited)
      continue;
    // cout << ptr_adj_nodes->id << ' ';

    ptr_adj_nodes->visited = true;
    ptr_adj_nodes->parent = ptr_source_node;

    if (ptr_adj_nodes->id == des_id) {
      pathExist = true;
      path_seq = new SingleLL(ptr_adj_nodes->id);
      return pathExist;
    }

    pathExist = depthSearch(ptr_adj_nodes, des_id, path_seq);

    if (pathExist) {
      path_seq->appendToTail(ptr_adj_nodes->id);
      return pathExist;
    }
  }

  return pathExist;
}

bool breadthSearch(GraphNode *ptr_source_node, int des_id,
                   SingleLL *&path_seq) {
  queue<GraphNode *> process_queue;
  GraphNode *current_node = NULL;
  process_queue.push(ptr_source_node);
  bool pathExist = false;

  while (!process_queue.empty()) {
    current_node = process_queue.front();
    // cout << current_node->id << ' ';

    if (current_node->visited) {
      process_queue.pop();
      continue;
    }

    if (current_node->id == des_id) {
      pathExist = true;
      break;
    }

    for (auto ptr_adj_nodes : current_node->adj) {
      if (ptr_adj_nodes->visited == true)
        continue;
      if (ptr_adj_nodes->parent == NULL)
        ptr_adj_nodes->parent = current_node;
      process_queue.push(ptr_adj_nodes);
    }

    current_node->visited = true;
    process_queue.pop();
  }

  queue<GraphNode *> empty_queue;
  swap(process_queue, empty_queue); // clearing queue

  if (pathExist) {
    path_seq = new SingleLL(current_node->id);

    while (current_node->parent != NULL) {
      path_seq->appendToTail(current_node->parent->id);
      current_node = current_node->parent;
    }
  }

  return pathExist;
}

/*********************** trees **************************/

void print_binary_tree(BinTreeNode *head, TreeTraverseMode order) {

  if (order == INORDER) {
    if (head->left != NULL)
      print_binary_tree(head->left, order);
    cout << head->data << ", ";
    if (head->right != NULL)
      print_binary_tree(head->right, order);
  }

  else if (order == PREORDER) {
    cout << head->data << ", ";
    if (head->left != NULL)
      print_binary_tree(head->left, order);
    if (head->right != NULL)
      print_binary_tree(head->right, order);
  }

  else if (order == POSTORDER) {
    if (head->left != NULL)
      print_binary_tree(head->left, order);
    if (head->right != NULL)
      print_binary_tree(head->right, order);
    cout << head->data << ", ";
  }

  else
    cout << "given traversal order is not valid";
}

} // namespace myspace