自己动手“敲”微软100题系列四

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题目如下：

注意要找的路径是到叶节点，我之前以为是到其中某个节点都行。

下面上代码：

//参考：http://www.cnblogs.com/caidaxia/archive/2011/10/14/2212369.html//主要用了一个数组，类似于栈的结构去保存路径#include <iostream>#include <iomanip>#define MAX_HEIGHT 10using namespace std;//二叉树结构体struct BinaryTreeNode // a node in the binary tree{int m_nValue; // value of nodeBinaryTreeNode *m_pLeft; // left child of nodeBinaryTreeNode *m_pRight; // right child of node};//建立二叉树void buildBinTree(BinaryTreeNode *&root,int* chs) //{static int inputCharIndex=0; //局部静态变量，用于遍历chs数组int ch;ch=chs[inputCharIndex++];if (ch == NULL) //表示空节点{root=NULL;}else{root =new BinaryTreeNode; //必须开避空间root->m_pLeft= NULL;root->m_pRight= NULL;root->m_nValue=ch;buildBinTree(root->m_pLeft,chs);buildBinTree(root->m_pRight,chs);}}//前序遍历打印树    void printfBSTree(BinaryTreeNode* root){if (NULL == root){cout <<setfill(' ')<<setw(4)<<'#';return;}cout <<setfill(' ')<<setw(4)<<root->m_nValue;printfBSTree(root->m_pLeft);printfBSTree(root->m_pRight);return;}//打印某条路径信息void printPath(int path[],int top){for (int i=0;i<top;i++){cout << setw(5) << setfill(' ')<< path[i];}cout << endl;}//参考了文档，迭代找路径void helper(BinaryTreeNode * root, int sum, int path[], int top) {path[top++] = root->m_nValue;sum -= root->m_nValue;if (root->m_pLeft == NULL && root->m_pRight==NULL) {if (sum == 0) printPath(path, top);//一直到叶子节点为止} else {if (root->m_pLeft != NULL) helper(root->m_pLeft, sum, path, top);if (root->m_pRight!=NULL) helper(root->m_pRight, sum, path, top);}top --;sum += root->m_nValue;    //....}void printPaths(BinaryTreeNode * root, int sum) {int path[MAX_HEIGHT];helper(root, sum, path, 0);}void main(){//按中序遍历构建树，空节点用NULL表示int chs[]={10,5,4,NULL,NULL,7,NULL,NULL,12,NULL,NULL};int sum=22;BinaryTreeNode* root;buildBinTree(root,chs); cout << "前序遍历打印出树" << endl;printfBSTree(root);cout << endl << "和为 "<< sum << "有路径如下" << endl;printPaths(root,sum);//让控制台程序停留下while(1);}

下面是运行结果：

有什么问题，欢迎各位交流。

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