LeetCode - Algorithms - 111. Minimum Depth of Binary Tree

Problem

111. Minimum Depth of Binary Tree

Java

BFS

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/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public int minDepth(TreeNode root) {
        if (root == null) return 0;
        int h = 0;
        TreeNode node = null;
        Queue<TreeNode> queue = new LinkedList<TreeNode>();
        queue.offer(root);
        while (!queue.isEmpty()) {
            int size = queue.size();
            for (int i = 0; i < size; i++) {
                node = queue.poll();
                if (node.left != null) queue.add(node.left);
                if (node.right != null) queue.add(node.right);
                if (node.left == null && node.right == null)
                    return h+1;
            }
            h++;
        }
        return h;       
    }   
}

Submission Detail

  • 52 / 52 test cases passed.
  • Runtime: 0 ms, faster than 100.00% of Java online submissions for Minimum Depth of Binary Tree.
  • Memory Usage: 59.3 MB, less than 77.17% of Java online submissions for Minimum Depth of Binary Tree.