Merge pull request neetcode-gh#873 from ThBlitz/main

Add C solutions to 104-max-depth-of-binary-tree, 110-check-for-balanced-binary-tree, 226-invert-binary-tree & 543-diameter-of-binary-tree.

Author: Ahmad-A0

c/104-Maximum-Depth-Of-Binary-Tree.c

@@ -0,0 +1,28 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+
+int max(int a, int b) {
+    if (a > b) {
+        return a;
+    }
+    return b;
+}
+
+
+int maxDepth(struct TreeNode* root) {
+
+    if (root == NULL) {
+        return 0;
+    }
+    return max(
+        maxDepth(root -> left),
+        maxDepth(root -> right)
+    ) + 1;
+}
+

c/110-Balanced-Binary-Tree.c

@@ -0,0 +1,38 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+
+int max(int a, int b) {
+    if (a > b) {
+        return a;
+    }
+    return b;
+}
+
+
+int height(struct TreeNode* root) {
+    if (root == NULL) {
+        return -1;
+    }
+    return max(
+        height(root -> left),
+        height(root -> right)
+    ) + 1;
+}
+
+
+bool isBalanced(struct TreeNode* root) {
+
+    if (root == NULL) {
+        return true;
+    }
+    if (abs(height(root -> left) - height(root -> right)) < 2 && isBalanced(root -> left) && isBalanced(root -> right)) {
+        return true;
+    }
+    return false;
+}

c/226-Invert-Binary-Tree.c

@@ -0,0 +1,20 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+
+struct TreeNode *invertTree(struct TreeNode* root) {
+
+    if (root == NULL) {
+        return root;
+    }
+    struct TreeNode* inverted_right = invertTree(root -> right);
+    struct TreeNode* inverted_left = invertTree(root -> left);
+    root -> right = inverted_left;
+    root -> left = inverted_right;
+    return root;
+}

c/543-Diameter-Of-Binary-Tree.c

@@ -0,0 +1,33 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+
+int max(int a, int b) {
+    if (a > b) {
+        return a;
+    }
+    return b;
+}
+
+int recur(struct TreeNode* root, int* maxDiameter) {
+    if (root == NULL) {
+        return 0;
+    }
+    int leftHeight = recur(root -> left, maxDiameter);
+    int rightHeight = recur(root -> right, maxDiameter);
+    *maxDiameter = max(*maxDiameter, leftHeight + rightHeight);
+    return max(leftHeight, rightHeight) + 1;
+}
+
+int diameterOfBinaryTree(struct TreeNode* root) {
+    int * maxDiameter;
+    int result = 0;
+    maxDiameter = &result;
+    recur(root, maxDiameter);
+    return result;
+}