leetcode-106. Construct Binary Tree from Inorder and Postorder Traversal

题目：

Given inorder and postorder traversal of a tree, construct the binary tree
You may assume that duplicates do not exist in the tree.

这题思路很前一题一模一样，这里不再赘述leetcode-105. Construct Binary Tree from Preorder and Inorder Traversal

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public TreeNode buildTree(int[] inorder, int[] postorder) {        return helper(inorder,0,inorder.length-1,postorder,0,postorder.length-1);    }    private TreeNode helper(int[] inorder, int il, int ir, int[] postorder, int pl, int pr){        if(il>ir) return null;        if(il==ir)return new TreeNode(inorder[ir]);        int t = 0;        for(int i = il ; i <= ir ; i++){            if(inorder[i]==postorder[pr]){                t = i;                break;            }        }        // System.out.println(il+" "+ir+" "+pl+" "+pr+" "+t);        TreeNode ret = new TreeNode(postorder[pr]);        ret.left = helper(inorder,il,t-1,postorder,pl,pr+t-ir-1);        ret.right = helper(inorder,t+1,ir,postorder,pr+t-ir,pr-1);        return ret;    }}