aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--balanced_binary_tree.c27
-rw-r--r--balanced_binary_tree.py34
2 files changed, 61 insertions, 0 deletions
diff --git a/balanced_binary_tree.c b/balanced_binary_tree.c
new file mode 100644
index 0000000..c42ec00
--- /dev/null
+++ b/balanced_binary_tree.c
@@ -0,0 +1,27 @@
+// 110. Balanced Binary Tree
+#include "leetcode.h"
+
+// given a binary tree, determine if it is height balanced
+
+int depth(struct TreeNode *root) {
+ if (!root)
+ return 0;
+ return fmax(depth(root->left), depth(root->right)) + 1;
+}
+
+bool isBalanced(struct TreeNode *root) {
+ if (!root)
+ return true;
+ return isBalanced(root->left) && isBalanced(root->right) &&
+ !(abs(depth(root->left) - depth(root->right)) > 1);
+}
+
+int main() {
+ int r1i[] = {3, 9, 20, -1, -1, 15, 7}, r2i[] = {1, 2, 2, 3, 3, -1, -1, 4, 4};
+ struct TreeNode *r1 = treenode_build(r1i, ARRAY_SIZE(r1i));
+ struct TreeNode *r2 = treenode_build(r2i, ARRAY_SIZE(r2i));
+ printf("%d\n", isBalanced(r1)); // expect: 1
+ printf("%d\n", isBalanced(r2)); // expect: 0
+ treenode_free(r1);
+ treenode_free(r2);
+}
diff --git a/balanced_binary_tree.py b/balanced_binary_tree.py
new file mode 100644
index 0000000..a677b56
--- /dev/null
+++ b/balanced_binary_tree.py
@@ -0,0 +1,34 @@
+# 110. Balanced Binary Tree
+import leetcode
+
+"""
+given a binary tree, determine if it is height balanced
+"""
+
+
+class Solution(object):
+ def isBalanced(self, root):
+ """
+ :type root: Optional[TreeNode]
+ :rtype: bool
+ """
+ self.balanced = True
+
+ def dfs(node):
+ if not node:
+ return 0
+ l, r = dfs(node.left), dfs(node.right)
+ if abs(l - r) > 1:
+ self.balanced = False
+ return max(l, r) + 1
+
+ dfs(root)
+ return self.balanced
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ r1 = leetcode.treenode_build(vals=[3, 9, 20, None, None, 15, 7])
+ r2 = leetcode.treenode_build(vals=[1, 2, 2, 3, 3, None, None, 4, 4])
+ print(obj.isBalanced(r1))
+ print(obj.isBalanced(r2))