面试题23：二叉树中和为某一值的路径

来源：互联网发布：淘宝文案范文编辑：程序博客网时间：2024/05/22 09:31

代码：

#include "stdafx.h"#include <iostream>#include <vector>using namespace std;struct BinaryTreeNode{int  m_nValue;BinaryTreeNode *m_pLeft;BinaryTreeNode *m_pRight;};void FindPath(BinaryTreeNode *pRoot, int nSum, vector<int>& path){if (pRoot == NULL || nSum == 0){return;}if (pRoot->m_nValue == nSum && pRoot->m_pLeft == NULL && pRoot->m_pRight == NULL){  vector<int>::iterator iter = path.begin();  for (; iter!=path.end(); iter++)  {  cout << *iter << " ";  }  cout << pRoot->m_nValue << endl;  return;  }path.push_back(pRoot->m_nValue);if (pRoot->m_pLeft != NULL){FindPath(pRoot->m_pLeft, nSum-pRoot->m_nValue, path);}if (pRoot->m_pRight != NULL){FindPath(pRoot->m_pRight, nSum-pRoot->m_nValue, path);}path.pop_back();}//以先序的方式构建二叉树，输入#表示结点为空void CreateBinaryTree(BinaryTreeNode *&pRoot){int nNodeValue = 0;cin >> nNodeValue;if (-1 == nNodeValue){pRoot = NULL;return; }else{pRoot = new BinaryTreeNode();pRoot->m_nValue = nNodeValue;CreateBinaryTree(pRoot->m_pLeft);CreateBinaryTree(pRoot->m_pRight);}}void PrintInOrder(BinaryTreeNode *&pRoot){if (pRoot != NULL){PrintInOrder(pRoot->m_pLeft);cout << pRoot->m_nValue << " ";PrintInOrder(pRoot->m_pRight);}}int _tmain(int argc, _TCHAR* argv[]){BinaryTreeNode *pRoot = NULL;CreateBinaryTree(pRoot);PrintInOrder(pRoot);cout << endl;vector<int> path;FindPath(pRoot, 22, path);system("pause");return 0;}

说明：用vector模拟实现栈的功能，而不是用stack，是因为在输出路径时，需要遍历栈中的元素，而stack只能取栈顶元素，stack不是最好的选择