求二叉树中核为某一值的所有路径

2013-07-01 16:50:53

求二叉树中核为某一值的所有路径

小结：

转化为二叉树的前序遍历

代码：

#include <iostream>
#include <assert.h>
#include <stack>
#include <vector>
using namespace std;

typedef int DataType;        //数中结点数据类型
const DataType END = -1;  //结束字符

typedef struct node
{
    DataType data;
    node * lchild;
    node * rchild;
}BTNode,*PBTNode;

//创建二叉树
PBTNode CreatBTree()
{
    PBTNode pNode = NULL;
    DataType data;
    cout<<"please enter the data of the node ,end with "<<END<<endl;
    cin>>data;
    if (END != data)
    {
        pNode = new BTNode;
        assert(NULL != pNode);
        pNode->data = data;
        pNode->lchild = CreatBTree();
        pNode->rchild = CreatBTree();
        return pNode;
    }
    else
    {
        return NULL;
    }
}

void PrintPath(stack <PBTNode> pStack)
{
    PBTNode pBTNode = NULL;
    while( !pStack.empty() )
    {
        pBTNode = pStack.top();
        pStack.pop();
        PrintPath(pStack);
        cout<<pBTNode->data<<"	";
    }
}
//
//void BinaryTreePathSum(PBTNode pRoot,int PathSum)
//{
//    PBTNode pCur = pRoot;
//    stack <PBTNode> pStack;
//    int PathSumCur = 0;
//    //PBTNode pBTNode = NULL;
//
//    while (NULL != pCur || !pStack.empty())
//    {
//        while (NULL != pCur)
//        {
//            while (NULL != pCur)
//            {
//                pStack.push(pCur);
//                PathSumCur = PathSumCur + pCur->data;
//                pCur = pCur->lchild;
//            }
//
//            pCur = pCur->rchild;
//        }
//
//        if (PathSumCur == PathSum)
//        {
//            PrintPath(pStack);
//        }
//        
//        if ( !pStack.empty() )
//        {
//            pCur = pStack.top();
//            pStack.pop();
//            PathSumCur = PathSumCur - pCur->data;
//        }
//
//        if ( !pStack.empty() )
//        {
//            pCur = pStack.top().rchild;
//        }
//        else
//        {
//            break;
//        }
//    }
//}

//找出和为某一值的所有路径
void FindPath(PBTNode pRoot,vector <int> PathVector,int ExpectedSum,int CurrentSum)
{
    PathVector.push_back(pRoot->data);
    CurrentSum = CurrentSum + pRoot->data;

    bool IsLeaf = (pRoot->lchild == NULL && pRoot->rchild == NULL);
    if ( (CurrentSum == ExpectedSum) && IsLeaf)
    {
        cout<<"1 path is found ,the path is :"<<endl;
        vector<int>::iterator iter;
        for (iter = PathVector.begin();iter != PathVector.end();++iter)
        {
            cout<<*iter<<"	";
        }
        cout<<endl;
    }

    if (NULL != pRoot->lchild)
    {
        FindPath(pRoot->lchild,PathVector,ExpectedSum,CurrentSum);
    }
    if (NULL != pRoot->rchild)
    {
        FindPath(pRoot->rchild,PathVector,ExpectedSum,CurrentSum);
    }

    CurrentSum = CurrentSum - pRoot->data;
    PathVector.pop_back();
}

//找出和为某一值的所有路径
void FindPath(PBTNode pRoot,int ExpectedSum)
{
    if (NULL == pRoot)
    {
        return;
    }
    vector <int> PathVector;
    int CurrentSum = 0;
    FindPath(pRoot,PathVector,ExpectedSum,CurrentSum);
}

//前序遍历打印二叉树
void PrintBTree(PBTNode pRoot)
{
    if (NULL != pRoot)
    {
        cout<<pRoot->data<<"	";
        PrintBTree(pRoot->lchild);
        PrintBTree(pRoot->rchild);
    }
}

//测试代码
int main()
{
    PBTNode pRoot = NULL;
    int ExpectedSum;
    //创建二叉树
    pRoot = CreatBTree();
    cout<<"the original binary tree is :"<<endl;
    PrintBTree(pRoot);
    cout<<endl;

    //测试FindPath
    cout<<"please enter the ExpectedSum ,end with "<<END<<endl;
    cin>>ExpectedSum;
    while (END != ExpectedSum)
    {
        FindPath(pRoot,ExpectedSum);
        cout<<"please enter the ExpectedSum ,end with "<<END<<endl;
        cin>>ExpectedSum;
    }

    return 0;
}

运行结果：

please enter the data of the node ,end with -1
10 5 4 -1 -1 7 -1 -1 12 -1 -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
please enter the data of the node ,end with -1
the original binary tree is :
10      5       4       7       12
please enter the ExpectedSum ,end with -1
22
1 path is found ,the path is :
10      5       7
1 path is found ,the path is :
10      12
please enter the ExpectedSum ,end with -1
19
1 path is found ,the path is :
10      5       4
please enter the ExpectedSum ,end with -1
23
please enter the ExpectedSum ,end with -1
-1
请按任意键继续. . .