!!!树的中序,前序线索化遍历

class A{
public:
///inorderMorrisTraversal
void inorderMorrisTraversal(TreeNode *root){
TreeNode *curr = root;
TreeNode *prev = nullptr;
while(curr!=nullptr){
if(curr->left == nullptr){
cout<<curr->val<<" ";
curr = curr->right;
}else{
///search predecessor
prev = curr->left;
while(prev->right !=nullptr && prev->right!=curr){
prev = prev->right;
}
if(prev->right==nullptr){
prev->right = curr;
curr = curr->left;
}else{
prev->right = nullptr;///recover the tree
cout<<curr->val<<" ";
curr = curr->right;
}
}///if-else
}///while
}
};

///
void preMorris(TreeNode* root){
TreeNode *curr = root;
TreeNode *prev = nullptr;
while(curr!=nullptr){
if(curr->left==nullptr){
cout<<curr->val<<" ";
curr = curr->right;
}else{
prev = curr->left;
while(prev->right!=nullptr && prev->right!=curr){
prev = prev->right;
}
if(prev->right==nullptr){
prev->right = curr;
cout<<curr->val<<" ";
curr = curr->left;
}else{
prev->right = curr;
curr = curr->right;
}
}
}///while
}