题目:
请实现两个函数,分别用来序列化和反序列化二叉树
牛客网上通过的代码:
class Solution {
private:
TreeNode* decode(char *&str) {
if(*str=='#'){
str++;
return NULL;
}
int num = 0;
while(*str != ',')
num = num*10 + (*(str++)-'0');
str++;
TreeNode *root = new TreeNode(num);
root->left = decode(str);
root->right = decode(str);
return root;
}
public:
char* Serialize(TreeNode *root) {
if(!root) return "#";
string r = to_string(root->val);
r.push_back(',');
char *left = Serialize(root->left);
char *right = Serialize(root->right);
char *ret = new char[strlen(left) + strlen(right) + r.size()];
strcpy(ret, r.c_str());
strcat(ret, left);
strcat(ret, right);
return ret;
}
TreeNode* Deserialize(char *str) {
return decode(str);
}
};
《剑指offer》上的代码,更容易理解:
void Serialize( BinaryTreeNode* pRoot, ostream& stream )
{
if ( pRoot == NULL )
{
stream << "$,";
return ;
}
stream << pRoot->m_nvalue << ',';
Serialize( pRoot->m_pLeft, stream );
Serialize( pRoot->m_pRight, stream );
}
void Deserialize( BinaryTreeNode** pRoot, istream& stream )
{
int number;
if ( ReadStream( stream, &number ) )
{
*pRoot = new BinaryTreeNode();
(*pRoot)->m_nvalue = number;
(*pRoot)->m_pLeft = NULL;
(*pRoot)->m_pRight = NULL;
Deserialize( &((*pRoot)->m_pLeft), stream );
Deserialize( &((*pRoot)->m_pRight), stream );
}
}