参考回答：
//算法1
#include <iostream>#include <fstream>#include <string>struct TreeNode{struct TreeNode* left;struct TreeNode* right;char elem;}; TreeNode* BinaryTreeFromOrderings(char* inorder, char* preorder, int length){if(length == 0){return NULL;}TreeNode* node = new TreeNode;node->elem = *preorder;int rootIndex = 0;for(;rootIndex < length; rootIndex++){if(inorder[rootIndex] == *preorder)break;}node->left = BinaryTreeFromOrderings(inorder, preorder +1, rootIndex);node->right = BinaryTreeFromOrderings(inorder + rootIndex + 1, preorder + rootIndex + 1, length - (rootIndex + 1));std::cout<<node->elem<<std::endl;free(node);return NULL;}int main(int argc, char** argv){char* pr="GDAFEMHZ";char* in="ADEFGHMZ"; BinaryTreeFromOrderings(in, pr, 8); printf("n"); return 0;}
