From 71667df0d7b2bbbdb16b2db6cea72d50a9ac48c9 Mon Sep 17 00:00:00 2001
From: Rahul Rajeev Pillai <66192267+Ashborn-SM@users.noreply.github.com>
Date: Sun, 4 Jul 2021 20:39:05 +0530
Subject: [PATCH] chore(C): add binary search tree (#376)

Co-authored-by: Ujjwal <75884061+UG-SEP@users.noreply.github.com>
Co-authored-by: Anirudh Kaushal <anirudh09041@gmail.com>
Co-authored-by: Ujjwal <75884061+UG-SEP@users.noreply.github.com>
---
 algorithms/C/README.md                 |   1 +
 algorithms/C/tree/binary-search-tree.c | 123 +++++++++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 algorithms/C/tree/binary-search-tree.c

diff --git a/algorithms/C/README.md b/algorithms/C/README.md
index 862ac8b2..0b19e6e1 100644
--- a/algorithms/C/README.md
+++ b/algorithms/C/README.md
@@ -36,6 +36,7 @@
  ## Tree
 - [Height Of Tree](tree/height-of-a-tree.c)
 - [Max and Min Element Of Tree](tree/min-and-max-of-tree.c)
+- [Binary Search Tree](tree/binary-search-tree.c)
 
 ## Searching
 - [Binary Search](searching/Binary-search.c)
diff --git a/algorithms/C/tree/binary-search-tree.c b/algorithms/C/tree/binary-search-tree.c
new file mode 100644
index 00000000..2a8b1e79
--- /dev/null
+++ b/algorithms/C/tree/binary-search-tree.c
@@ -0,0 +1,123 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+struct node{
+	struct node* left;
+	struct node* right;
+	int val;
+};
+
+struct node* createNode(int val){
+	struct node* n = (struct node*)malloc(sizeof(struct node));
+	n->val = val;
+	n->left = NULL;
+	n->right = NULL;
+	return n;
+}
+
+struct node* insert(struct node* root, int val){
+	if(root == NULL){
+		root = createNode(val);
+	}
+	else if(root->val < val){
+		root->right = insert(root->right, val);
+	}
+	else{
+		root->left = insert(root->left, val);
+	}
+
+	return root;
+}
+
+bool is_full(struct node* root){
+	if(root == NULL || (root->left == NULL && root->right == NULL)){
+		return true;
+	}
+	else if(root->left != NULL && root->right != NULL){
+		return is_full(root->left) && is_full(root->right);
+	}
+	return false;
+}
+
+int depth(struct node* root){
+	int d = 0;
+	while(root != NULL){
+		root = root->left;
+		d++;
+	}
+	return d;
+}
+
+bool is_perfect(struct node* root, int depth, int current_lvl){
+	if(root == NULL){
+		return true; 
+	}
+	else if(root->left == NULL && root->right == NULL){
+		return depth == current_lvl;
+	}
+	else if(root->left != NULL && root->right != NULL){
+		return is_perfect(root->left, depth, 1+current_lvl) &&
+		is_perfect(root->right, depth, 1+current_lvl);
+	}
+	
+	return false;
+}
+
+void print(struct node* root){
+	if(root != NULL){
+		print(root->left);
+		printf("%i ", root->val);
+		print(root->right);
+	}
+}
+
+void deallocate(struct node** root){
+	if(*root != NULL){
+		deallocate(&(*root)->left);
+		deallocate(&(*root)->right);
+		free(*root);
+		*root = NULL;
+	}
+}
+
+int main(){
+	struct node* root = NULL;
+
+	root = insert(root, 37);
+	root = insert(root, 19);
+	root = insert(root, 4);
+	root = insert(root, 22);
+	root = insert(root, 51);
+	root = insert(root, 55);
+	root = insert(root, 42);
+	
+	if(is_full(root)){
+		printf("BST is full\n");
+	}
+	else{
+		printf("BST is not full\n");
+	}
+	if(is_perfect(root, depth(root)-1, 0)){ 
+		printf("BST is Perfect\n");
+	}
+	else{
+		printf("BST is not Perfect\n");
+	}
+	print(root);
+	/*
+		Tree structure
+	       37
+	      /  \
+	     19  51
+	    / \  / \
+	   4  22 42 55
+
+		Output:
+			BST is full
+			BST is Perfect
+			4 19 22 37 42 51 55
+	*/
+	deallocate(&root);
+	return 0;
+}