二叉树的所有路径

/*
问题描述：给一棵二叉树，找出从根节点到叶子节点的所有路径。
来源：LintCode
作者：syt

日期：2017-11-10

思路：迭代找出叶子节点并记录中间的寻找过程

*/

#include <iostream>class TreeNode{public:int val;TreeNode *left, *right;TreeNode(){}TreeNode(int val, TreeNode *lptr = NULL, TreeNode *rptr = NULL) {this->val = val;this->left = lptr;this->right = rptr;}};

#include "d_tree.h"#include <vector>#include <string>using namespace std;void findPaths(TreeNode *node, vector<string> &allPath, string path){if (node->left == NULL && node->right == NULL){allPath.push_back(path);return;}//path = path + "->" + to_string(node->val);if (node->left != NULL)findPaths(node->left, allPath, path + "->" + to_string(node->left->val));if (node->right != NULL)findPaths(node->right, allPath, path + "->" + to_string(node->right->val));}/*** @param root the root of the binary tree* @return all root-to-leaf paths*/vector<string> binaryTreePaths(TreeNode* root) {// Write your code herevector<string> result;if (root != NULL){string path = to_string(root->val);findPaths(root, result, path);}return result;}TreeNode *buildTree(int n){TreeNode *root, *b, *c, *d, *e, *f, *g, *h;switch (n){case 1:e = new TreeNode(3);d = new TreeNode(2);c = new TreeNode(4);b = new TreeNode(2, d, e);root = new TreeNode(1, b, c);break;case 2:h = new TreeNode(9);g = new TreeNode(7);f = new TreeNode(6);e = new TreeNode(5);d = new TreeNode(4, g, h);c = new TreeNode(3, e, f);b = new TreeNode(2, d, (TreeNode *)NULL);root = new TreeNode(1, b, c);break;}return root;}void main(){TreeNode *root = buildTree(1);vector<string> result = binaryTreePaths(root);for (int i = 0; i < result.size(); i++){cout << result[i] << endl;}}