前序
void frontOrder(TreeNode* root)
{
if(!root) return;
if(!root->left&&!root->right)
{
front.push_back(root->val);
return;
}
front.push_back(root->val);
if(root->left) frontOrder(root->left);
if(root->right) frontOrder(root->right);
return;
}
中序
void middleOrder(TreeNode* root)
{
if(!root) return;
if(!root->left&&!root->right)
{
middle.push_back(root->val);
return;
}
if(root->left) middleOrder(root->left);
middle.push_back(root->val);
if(root->right) middleOrder(root->right);
return;
}
后序
void postOrder(TreeNode* root)
{
if(!root) return;
if(!root->left&&!root->right)
{
post.push_back(root->val);
return;
}
if(root->left) postOrder(root->left);
if(root->right) postOrder(root->right);
post.push_back(root->val);
return;
}