104 Maximum Depth of Binary Tree – Easy
Problem:
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.
Thoughts:
Very straight forward with recursion.
Solutions:
Iterative way:
/**
* 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;
}
Queue<TreeNode> q = new LinkedList<TreeNode>();
q.add(root);
int count = 0;
while (q.size() > 0) {
int n = q.size();
count++;
for (int i = 0; i < n; i ++) {
TreeNode node = q.remove();
if (node.left != null) {
q.add(node.left);
}
if (node.right !=null) {
q.add(node.right);
}
}
}
return count;
}
}
Recursion way:
public class Solution {
public int maxDepth(TreeNode root) {
if (root == null) {
return 0;
}
return Math.max(maxDepth(root.left), maxDepth(root.right)) + 1;
}
}