practice_dsa/problems/cpp/trees/TopViewTree/tvt.cpp at main · Parihar07/practice_dsa · 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
#include<iostream>
#include<unordered_map>
#include<queue>

using namespace std;

struct TreeNode {
  int val;
  TreeNode* left;
  TreeNode* right;
  TreeNode(int x) : val(x), left(NULL), right(NULL) {}
} *root;

void printLevelOrder(TreeNode* R);
void createTree();
void printPreOrder(TreeNode* R);
vector<int> topViewTree(TreeNode* A);
vector<int> topViewTreeIterative(TreeNode* A);
void topViewRecursive(TreeNode* r, int d, int& s, int& e);

void createTree()
{
  TreeNode* R = new TreeNode(2);
  R->left = new TreeNode(3);
  R->right = new TreeNode(4);
  R->left->left = new TreeNode(5);
  R->left->right = new TreeNode(6);
  R->left->left->left = new TreeNode(9);
  R->left->left->right = new TreeNode(10);
  R->right->left = new TreeNode(8);
  R->right->right = new TreeNode(7);
  R->right->right->left = new TreeNode(13);
  R->right->right->right = new TreeNode(14);
  R->right->right->right->left = new TreeNode(15);
  root = R;
}
void printLevelOrder(TreeNode* R)
{
  queue<TreeNode*> Q;
  Q.push(R);
  while (!Q.empty())
  {
	int N = Q.size();
	for (int i = 0; i < N; i++)
	{
	  TreeNode* t = Q.front();
	  cout << t->val << " ";
	  if (t->left != NULL) Q.push(t->left);
	  if (t->right != NULL) Q.push(t->right);
	  Q.pop();
	}
	cout << endl;
  }
}
void printPreOrder(TreeNode* R)
{
  if (R == NULL)
	return;
  cout << R->val << " ";
  printPreOrder(R->left);
  printPreOrder(R->right);
}

struct TreeInfo {
  TreeNode* R;
  int axis;
  TreeInfo(TreeNode* r, int x) :R(r), axis(x) {};
};

vector<int> topViewTreeIterative(TreeNode* A)
{
  vector<int> ans;
  unordered_map<int, int> um;
  queue<TreeInfo*> Q;
  Q.push(new TreeInfo(A, 0));
  int maxi = INT_MIN, mini = INT_MAX;

  while (!Q.empty())
  {
	TreeInfo* t = Q.front();
	if (um.find(t->axis) == um.end())
	{
	  um[t->axis] = t->R->val;
	  maxi = max(maxi, t->axis);
	  mini = min(mini, t->axis);
	}

	if (t->R->left != NULL)
	{
	  Q.push(new TreeInfo(t->R->left, t->axis - 1));
	}
	if (t->R->right != NULL)
	{
	  Q.push(new TreeInfo(t->R->right, t->axis + 1));
	}

	Q.pop();
  }
  for (int i = mini; i <= maxi; i++)
  {
	ans.push_back(um[i]);
  }
  return ans;
}

unordered_map<int, int>gUM;

void topViewRecursive(TreeNode* r, int d, int& s, int& e)
{
  if (r == NULL)
	return;
  if (gUM.find(d) == gUM.end())
  {
	gUM[d] = r->val;
	s = max(s, d);
	e = min(e, d);
  }
  topViewRecursive(r->left, d - 1, s, e);
  topViewRecursive(r->right, d + 1, s, e);
}

vector<int> topViewTree(TreeNode* A)
{
  int maxi = INT_MIN, mini = INT_MAX;
  vector<int> ans;
  topViewRecursive(A, 0, maxi, mini);
  for (int i = mini; i <= maxi; i++)
  {
	ans.push_back(gUM[i]);
  }
  return ans;
}
int main()
{
  cout << "Hello top view\n";
  createTree();
  TreeNode* t = root;
  //printLevelOrder(t);
  vector<int> ans = topViewTree(t);
  for (auto a = ans.begin(); a != ans.end(); a++)
  {
	cout << *a << " ";
  }
  cout << endl;
  return 0;
}