TheAlgorithms-C-Plus-Plus/data_structure/Binary Search Tree.cpp

#include <iostream>
using namespace std;

struct node
{
	int val;
	node *left;
	node *right;
};

struct queue
{
	node *t[100];
	int front;
	int rear;
};

queue q;

void enqueue(node *n)
{
	q.t[q.rear++] = n;
}

node *dequeue()
{
	return (q.t[q.front++]);
}

void Insert(node *n, int x)
{
	if (x < n->val)
	{
		if (n->left == NULL)
		{
			node *temp = new node;
			temp->val = x;
			temp->left = NULL;
			temp->right = NULL;
			n->left = temp;
		}
		else
		{
			Insert(n->left, x);
		}
	}
	else
	{
		if (n->right == NULL)
		{
			node *temp = new node;
			temp->val = x;
			temp->left = NULL;
			temp->right = NULL;
			n->left = temp;
		}
		else
		{
			Insert(n->right, x);
		}
	}
}

int findMaxInLeftST(node *n)
{
	while (n->right != NULL)
	{
		n = n->right;
	}
	return n->val;
}

void Remove(node *p, node *n, int x)
{
	if (n->val == x)
	{
		if (n->right == NULL && n->left == NULL)
		{
			if (x < p->val)
			{
				p->right = NULL;
			}
			else
			{
				p->left = NULL;
			}
		}
		else if (n->right == NULL)
		{
			if (x < p->val)
			{
				p->right = n->left;
			}
			else
			{
				p->left = n->left;
			}
		}
		else if (n->left == NULL)
		{
			if (x < p->val)
			{
				p->right = n->right;
			}
			else
			{
				p->left = n->right;
			}
		}
		else
		{
			int y = findMaxInLeftST(n->left);
			n->val = y;
			Remove(n, n->right, y);
		}
	}
	else if (x < n->val)
	{
		Remove(n, n->left, x);
	}
	else
	{
		Remove(n, n->right, x);
	}
}

void BFT(node *n)
{
	if (n != NULL)
	{
		cout << n->val << "  ";
		enqueue(n->left);
		enqueue(n->right);
		BFT(dequeue());
	}
}

void Pre(node *n)
{
	if (n != NULL)
	{
		cout << n->val << "  ";
		Pre(n->left);
		Pre(n->right);
	}
}

void In(node *n)
{
	if (n != NULL)
	{
		In(n->left);
		cout << n->val << "  ";
		In(n->right);
	}
}

void Post(node *n)
{
	if (n != NULL)
	{
		Post(n->left);
		Post(n->right);
		cout << n->val << "  ";
	}
}

int main()
{
	q.front = 0;
	q.rear = 0;
	int value;
	int ch;
	node *root = new node;
	cout << "\nEnter the value of root node :";
	cin >> value;
	root->val = value;
	root->left = NULL;
	root->right = NULL;
	do
	{
		cout << "\n1. Insert";
		cout << "\n2. Delete";
		cout << "\n3. Breadth First";
		cout << "\n4. Preorder Depth First";
		cout << "\n5. Inorder Depth First";
		cout << "\n6. Postorder Depth First";

		cout << "\nEnter Your Choice : ";
		cin >> ch;
		int x;
		switch (ch)
		{
		case 1:
			cout << "\nEnter the value to be Inserted : ";
			cin >> x;
			Insert(root, x);
			break;
		case 2:
			cout << "\nEnter the value to be Deleted : ";
			cin >> x;
			Remove(root, root, x);
			break;
		case 3:
			BFT(root);
			break;
		case 4:
			Pre(root);
			break;
		case 5:
			In(root);
			break;
		case 6:
			Post(root);
			break;
		}
	} while (ch != 0);
}