Given a binary tree, find its minimum depth.
The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.
/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public int minDepth(TreeNode root) { if(root == null) return 0; if(root.left == null && root.right == null) return 1; int leftDepth = minDepth(root.left); int rightDepth = minDepth(root.right); if(leftDepth == 0){ return rightDepth + 1; }else if(rightDepth == 0){ return leftDepth + 1; }else{ return Math.min(leftDepth, rightDepth)+1; } } }