非递归
public class Problem {
public List<Integer> inorderTraversal(TreeNode root) {
// write your code here
List<Integer> list = new LinkedList<>();
if(root==null){
return list;
}
Stack<TreeNode> stack = new Stack<>();
TreeNode node = root;
while (node!=null||!stack.isEmpty()){
while (node!=null){
stack.push(node);
node=node.left;
}
if(!stack.isEmpty()){
node = stack.pop();
list.add(node.val);
if(node.right!=null){
node=node.right;
}else {
node=null;
}
}
}
return list;
}
}
递归
public class Problem {
public static void main(String[] args) {
}
public List<Integer> inorderTraversal(TreeNode root) {
// write your code here
List<Integer> list = new LinkedList<>();
if(root==null){
return list;
}
inorderTraverSalCore(root,list);
return list;
}
public void inorderTraverSalCore(TreeNode root,List<Integer> list){
if(root==null){
return;
}
inorderTraverSalCore(root.left,list);
list.add(root.val);
inorderTraverSalCore(root.right,list);
}
}