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.
找出二叉树的最小深度.
//深度优先 维护最小深度
public int minDepth(TreeNode root) {
if(root ==null){//递归结束
return 0;
}
int left = minDepth(root.left);
int right = minDepth(root.right);
if(left!=0 && right!=0){
return Math.min(left, right)+1;//当前节点最小深度
}
if(left ==0){
return right+1;
}
return left+1;
}
