#include<iostream>
#include "Queue.h"
using namespace std;//节点结构体
struct BinaryTreeNode
{BinaryTreeNode* father = NULL;//指向父节点BinaryTreeNode* left = NULL;BinaryTreeNode* right = NULL;int arrived = 0;//记录子树深度值到达的数目。取值为0或1或2int depth = 0;//以此节点为根的树的深度int longstpath = 0;//以此节点为根的树中的最长路径bool stored = false;//是否已入列等待
};//取大值
int max2(int a, int b)
{if (a > b)return a;else return b;
}//取大值
int max3(int a, int b, int c)
{return max2(max2(a, b), c);
}//依据不同情况（有的节点无左/右子节点），更新longstpath
//longstpath一定是下面三数中的最大值：左子树的longstpath。右子树的longstpath。左右子树深度和+2
void SetLongstpath(BinaryTreeNode* temp)
{int lpath, rpath, ldepth, rdepth;if (temp->left){lpath = temp->left->longstpath;   ldepth = temp->left->depth;}else lpath = ldepth = 0;if (temp->right){rpath = temp->right->longstpath;   rdepth = temp->right->depth;}else rpath = rdepth = 0;temp->longstpath = max3(lpath, rpath, ldepth + rdepth + 2);//更新最长路径longstpath
}int FindPath(Queue<BinaryTreeNode*> &queue)
{BinaryTreeNode* temp;while (!queue.IsEmpty()){queue.Delete(temp);temp->stored = false;if (temp->arrived == 2)//子节点都到达了，万事俱备{SetLongstpath(temp);//更新temp的Longstpathif (temp->father)//若不是根节点。，则上移该节点（即对父节点进行处理）{temp->father->depth = max2(temp->father->depth, temp->depth + 1);//更新父节点的深度值temp->father->arrived++;//到达子节点数目+1if (!temp->father->stored)//说明这是第一个到达的子节点。该父节点从未入列，则将其入列{queue.Add(temp->father);temp->father->stored = true;}}else//根节点，返回longstpathreturn temp->longstpath;}if (temp->arrived == 1)//有子节点还没到，更新longstpath的条件不充分。又一次入列等待子节点{queue.Add(temp);temp->stored = true;}}
}void main()
{BinaryTreeNode* n1 = new BinaryTreeNode;BinaryTreeNode* n2 = new BinaryTreeNode;BinaryTreeNode* n3 = new BinaryTreeNode;BinaryTreeNode* n4 = new BinaryTreeNode;BinaryTreeNode* n5 = new BinaryTreeNode;BinaryTreeNode* n6 = new BinaryTreeNode;BinaryTreeNode* n7 = new BinaryTreeNode;BinaryTreeNode* n8 = new BinaryTreeNode;BinaryTreeNode* n9 = new BinaryTreeNode;BinaryTreeNode* n10 = new BinaryTreeNode;BinaryTreeNode* n11 = new BinaryTreeNode;//构造二叉树n2->father = n3->father = n1;n4->father = n5->father = n2;n6->father = n7->father = n4;n8->father = n9->father = n5;n10->father = n6;n11->father = n9;n6->left = n10;n4->left = n6; n4->right = n7;n9->left = n11;n5->left = n8; n5->right = n9;n2->left = n4; n2->right = n5;n1->left = n2; n1->right = n3;n3->arrived = 2;//叶节点初始为2n7->arrived = 2;n8->arrived = 2;n10->arrived = 2;n11->arrived = 2;n6->arrived = 1;//但孩子节点初始为1n9->arrived = 1;Queue<BinaryTreeNode*> queue;queue.Add(n3);n3->stored = true;queue.Add(n7);n7->stored = true;queue.Add(n8);n8->stored = true;queue.Add(n10);n10->stored = true;queue.Add(n11);n11->stored = true;cout << "最大路径长度:" << FindPath(queue) << endl;system("pause");
}