LeetCode CodeconstructBinaryTreeFromInorderAndPostorderTraversal中序，后序构造二叉树

// Date   : 2016.07.26// Author : yqtao// https://github.com/yqtaowhu/********************************************************************************** * * Given inorder and postorder traversal of a tree, construct the binary tree.* * Note:* You may assume that duplicates do not exist in the tree.* *               **********************************************************************************/#include <stdio.h>#include <vector>#include <queue>using namespace std;struct TreeNode {    int val;    TreeNode *left;    TreeNode *right;    TreeNode(int x) : val(x), left(NULL), right(NULL) {}};//递归的方法class Solution {public:    TreeNode* helper(vector<int>& inorder,int i,int j, vector<int>& postorder,int ii,int jj) {        if (i>j||ii>jj) return NULL;        int mid=postorder[jj];        TreeNode* root=new TreeNode(mid);        int index=0;        for ( index=i;index<=j;index++) {            if (inorder[index]==mid)                break;        }        int dis=index-i; //步数        root->left=helper(inorder,i,i+dis-1,postorder,ii,ii+dis-1);        root->right=helper(inorder,i+dis+1,j,postorder,ii+dis,jj-1);        return root;    }    TreeNode* buildTree(vector<int>& inorder, vector<int>& postorder) {        return helper(inorder,0,inorder.size()-1,postorder,0,postorder.size()-1);    }};