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MiddleSolution.java
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MiddleSolution.java
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import java.util.ArrayList;
import java.util.Deque;
import java.util.LinkedList;
import java.util.List;
/*二叉树 中序遍历*/
public class MiddleSolution {
public List<Integer> preorderTraversal(TreeNodeNew root) {
List<Integer> res = new ArrayList<Integer>();
preorder(root, res);
return res;
}
public void preorder(TreeNodeNew root, List<Integer> res) {
if (root == null) {
return;
}
preorder(root.left, res);
res.add(root.val);
preorder(root.right, res);
}
public List<Integer> inorderTraversal(TreeNodeNew root) {
List<Integer> res = new ArrayList<Integer>();
Deque<TreeNodeNew> stk = new LinkedList<TreeNodeNew>();
while (root != null || !stk.isEmpty()) {
while (root != null) {
stk.push(root);
root = root.left;
}
root = stk.pop();
res.add(root.val);
root = root.right;
}
return res;
}
}