LeetCode: 104. Maximum Depth of Binary Tree

LeetCode: 104. Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from

the root node down to the farthest leaf node.

自己的答案：

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
int left = maxDepth(root.left);
int right = maxDepth(root.right);
return Math.max(left, right) + 1;
}
}

最快的答案：

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class Solution {

int max = 0;
public int maxDepth(TreeNode root) {
if (root == null) return 0;
getDepth(root, 0);
return max;
}
private void getDepth(TreeNode root, int count) {
if (root == null) return;
count++;
if (root.left == null && root.right == null) {
max = Math.max(count, max);
}
getDepth(root.left, count);
getDepth(root.right, count);
}
}

Two Java Iterative solution DFS and BFS