输入二叉树为：ABD##E##C##。

运行环境：main.cpp

运行结果：3

#include "bits/stdc++.h"
using namespace std;
typedef struct BiTNode{char data;struct BiTNode *lchild,*rchild;int tag;
}BiTNode,*BiTree;void createTree(BiTree  &t){char ch;ch=getchar();if (ch=='#') t=NULL;else{t=(BiTNode *) malloc(sizeof (BiTNode));t->data=ch;t->tag=0;t->lchild=NULL;t->rchild=NULL;createTree(t->lchild);createTree(t->rchild);}
}
int btDepth(BiTree t){if (!t)return 0;int front=-1,rear=-1;int last=0,level=0;BiTree Q[100];Q[++rear]=t;BiTree p;while (front<rear){p=Q[++front];if (p->lchild)Q[++rear]=p->lchild;if (p->rchild)Q[++rear]=p->rchild;if (front==last){level++;last=rear;}}return level;
}
int main() {BiTree t;createTree(t);printf("%d", btDepth(t));}