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//============================================================================
// Name        : test.cpp
// Author      : will
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include<stdio.h>
#include<stdlib.h>

typedef struct BinaryTreeNode_{
  int value;
	BinaryTreeNode_* left;
	BinaryTreeNode_* right;
}BinaryTreeNode;

BinaryTreeNode* create(int* pre_start,int* pre_end,int* in_start,int* in_end){
	int root_value = pre_start[0];
	BinaryTreeNode* root = (BinaryTreeNode*)malloc(sizeof(BinaryTreeNode));
	root->value = root_value;
	root->left = root->right = NULL;

	//root只有left的时候
	if(pre_start == pre_end){
		if(in_start == in_end && *pre_start == *in_start){
			return root;
		}else{
			printf("input is invalid");
			return NULL;
		}
	}

	//求得中序中root的位置
	int* in_root = in_start;
	while(in_root <= in_end && *in_root != root_value){
		++in_root;
	}

	//root只有left的时候
	if(in_root == in_end && *in_root != root_value){
		printf("input is invalid");
		return NULL;
	}

	int left_len = in_root - in_start;

	if(left_len > 0){
		root->left = create(pre_start+1,pre_start+left_len,in_start,in_root-1);
	}
	if(left_len < pre_end - pre_start){
		root->right = create(pre_start+left_len+1,pre_end,in_root+1,in_end);
	}

	return root;
}

BinaryTreeNode* createTree(int* preorder,int* inorder,int len){
	if(preorder == NULL || inorder ==NULL || len <= 0){
		return NULL;
	}
	return create(preorder,preorder+len-1,inorder,inorder+len-1);
}

void postOrder(BinaryTreeNode* root){
	if(root){
		if(root->left){
			postOrder(root->left);
		}
		if(root->right){
			postOrder(root->right);
		}
		printf("%d ",root->value);
	}
}

int main(void)
{
	int a[] = {1,2,4,7,3,5,6,8};
	int b[] = {4,7,2,1,5,3,8,6};

	BinaryTreeNode* root = createTree(a,b,8);
	postOrder(root);
	return EXIT_SUCCESS;
}