tree

Author: vegetabledogg

331-Verify-Preorder-Serialization-of-a-Binary-Tree.c

@@ -0,0 +1,33 @@
+bool isValidSerialization(char* preorder) {
+    int node = 0, nullNode = 0, i;
+    for (i = 0; i < strlen(preorder); i++)
+    {
+        if ('#' == preorder[i])
+        {
+            nullNode++;
+        }
+        else
+        {
+            node++;
+        }
+        for ( ; i < strlen(preorder); i++)
+        {
+            if (',' == preorder[i])
+            {
+                break;
+            }
+        }
+        if (nullNode > node && i < strlen(preorder) - 1)
+        {
+            return false;
+        }
+    }
+    if (nullNode > node)
+    {
+        return true;
+    }
+    else
+    {
+        return false;
+    }
+}

450-Delete-Node-in-a-BST.c

@@ -0,0 +1,44 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+struct TreeNode* deleteNode(struct TreeNode* root, int key) {
+    if (NULL == root)
+    {
+        return root;
+    }
+    if (root->val > key)
+    {
+        root->left = deleteNode(root->left, key);
+    }
+    else if (root->val < key)
+    {
+        root->right = deleteNode(root->right, key);
+    }
+    else
+    {
+        if (NULL == root->left)
+        {
+            return root->right;
+        }
+        else if (NULL == root->right)
+        {
+            return root->left;
+        }
+        else
+        {
+            struct TreeNode *temp = root->right;
+            while (NULL != temp->left)
+            {
+                temp = temp->left;
+            }
+            root->val = temp->val;
+            root->right = deleteNode(root->right, temp->val);
+        }
+    }
+    return root;
+}

543-Diameter-of-Binary-Tree.c

@@ -0,0 +1,46 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     struct TreeNode *left;
+ *     struct TreeNode *right;
+ * };
+ */
+int max(int a, int b)
+{
+    return a > b ? a : b;
+}
+int height(struct TreeNode *root)
+{
+    if (NULL == root)
+    {
+        return -1;
+    }
+    return root->val;
+}
+int diameterOfBinaryTree(struct TreeNode* root) {
+    if (NULL == root)
+    {
+        return 0;
+    }
+    int lenth2 = diameterOfBinaryTree(root->left);
+    int lenth3 = diameterOfBinaryTree(root->right);
+    int leftHeight = height(root->left);
+    int rightHeight = height(root->right);
+    int lenth1 = 2 + leftHeight + rightHeight;
+    root->val = max(leftHeight, rightHeight) + 1;
+    int max;
+    if (lenth1 > lenth2)
+    {
+        max = lenth1;
+    }
+    else
+    {
+        max = lenth2;
+    }
+    if (max < lenth3)
+    {
+        max = lenth3;
+    }
+    return max;
+}