/*第 11 题（树）求二叉树中节点的最大距离...如果我们把二叉树看成一个图，父子节点之间的连线看成是双向的，我们姑且定义"距离"为两节点之间边的个数。写一个程序，求一棵二叉树中相距最远的两个节点之间的距离。start time 16:17end time 17:20*/#include <stdio.h>#include <stdlib.h>typedef struct BiTree{    int data;    BiTree * p_left, * p_right;}BiTree;void CreateBiTree(BiTree * &T){    int d;    printf("please input data number:");    scanf("%d", &d);    if (d != 0)    {        T = (BiTree *)malloc(sizeof(BiTree));        T->data =http://www.mamicode.com/ d;        T->p_left = NULL;        T->p_right = NULL;        CreateBiTree(T->p_left);        CreateBiTree(T->p_right);    }}//递归int maxdistance = 0;int  BiTreeMaxDistance(BiTree * T) //利用后序遍历{        if (T == NULL)    {        return -1;    }    else    {        int l = BiTreeMaxDistance(T->p_left);        int r = BiTreeMaxDistance(T->p_right);        int distance = l + r + 2;        maxdistance = (distance > maxdistance) ? distance : maxdistance;        return (l > r) ? l + 1 : r + 1;    }}int main(){    BiTree * T = NULL;    CreateBiTree(T);    BiTreeMaxDistance(T);    printf("the max distance of the tree is %d.\n", maxdistance);    return 0;}