111. Minimum Depth of Binary Tree

 

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.

 

class Solution {
    public int minDepth(TreeNode root) {
        if(root == null) return 0;
        int left = minDepth(root.left);
        int right = minDepth(root.right);
        return (left==0||right==0) ? left+right+1:Math.min(left,right)+1;
    }

}