//求二叉树的最小深度，dfs
public int MinDepth01(TreeNode root)
{
if (root == null)
{
return(0);
}
Stack <DeepVO> stack = new Stack <DeepVO>();
int deep = 9999;
stack.Push(new DeepVO(1, root));
while (stack.Count > 0)
{
DeepVO vo = stack.Pop();
if (vo.node.left == null && vo.node.right == null)
{
deep = Math.Min(vo.deep, deep);
}
else
{
if (vo.node.left != null)
{
stack.Push(new DeepVO(vo.deep + 1, vo.node.left)); //要注意n++和n+1的陷阱
}
if (vo.node.right != null)
{
stack.Push(new DeepVO(vo.deep + 1, vo.node.right));
}
}
}
return(deep);
}
//解法三：队列dfs求解
public int MinDepth03(TreeNode root)
{
if (root == null)
{
return(0);
}
Queue <DeepVO> que = new Queue <DeepVO>();
que.Enqueue(new DeepVO(1, root));
while (que.Count > 0)
{
DeepVO vo = que.Dequeue();
if (vo.node.left == null && vo.node.right == null)
{
return(vo.deep);
}
else
{
if (vo.node.left != null)
{
que.Enqueue(new DeepVO(vo.deep + 1, vo.node.left)); //要注意n++和n+1的陷阱
}
if (vo.node.right != null)
{
que.Enqueue(new DeepVO(vo.deep + 1, vo.node.right));
}
}
}
return(0);
}
