From 8fc3fadc94061b36380535cf6c9b51d43bec8754 Mon Sep 17 00:00:00 2001
From: linlihong <747682928@qq.com>
Date: Tue, 3 Sep 2024 09:35:48 +0800
Subject: [PATCH] =?UTF-8?q?2024/9/2=20Hot100=20binaryTree=20=E6=98=A8?=
 =?UTF-8?q?=E6=97=A5=E5=85=AC=E5=85=B1=E8=8A=82=E7=82=B9=E7=AC=AC=E4=BA=8C?=
 =?UTF-8?q?=E7=A7=8D=E8=A7=A3=E6=B3=95?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
 .../com/cool/hot100/binary_tree/Num236.java   | 60 ++++++++++++-------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/cool/hot100/binary_tree/Num236.java b/src/main/java/com/cool/hot100/binary_tree/Num236.java
index 57b3143..206b009 100644
--- a/src/main/java/com/cool/hot100/binary_tree/Num236.java
+++ b/src/main/java/com/cool/hot100/binary_tree/Num236.java
@@ -12,35 +12,51 @@ import java.util.*;
  * Level ?
  */
 public class Num236 {
+    //
+//    Map<Integer, TreeNode> map = new HashMap<>();
+//    LinkedList<TreeNode> list = new LinkedList<>();
+//    List<LinkedList<TreeNode>> linkedLists = new ArrayList<>();
+    private TreeNode res;
 
-    Map<Integer, TreeNode> map = new HashMap<>();
-    LinkedList<TreeNode> list = new LinkedList<>();
-    List<LinkedList<TreeNode>> linkedLists = new ArrayList<>();
 
     public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
-        if (root == null) return null;
+//        if (root == null) return null;
+//        dfs(root, p, q);
+//        TreeNode node = new TreeNode();
+//        LinkedList<TreeNode> treeNodes = linkedLists.get(0);
+//        for (TreeNode treeNode : treeNodes) {
+//            if (linkedLists.get(1).contains(treeNode)) {
+//                node = treeNode;
+//            }
+//        }
         dfs(root, p, q);
-        TreeNode node=new TreeNode();
-        LinkedList<TreeNode> treeNodes = linkedLists.get(0);
-        for (TreeNode treeNode : treeNodes) {
-            if(linkedLists.get(1).contains(treeNode)){
-                node=treeNode;
-            }
-        }
-        return node;
+        return this.res;
     }
 
-    private void dfs(TreeNode root, TreeNode p, TreeNode q) {
-        if (root == null) return;
-        list.add(root);
-        map.put(root.val, root);
-        if (root==p||root==q){
-            LinkedList<TreeNode> copyList = new LinkedList<>(list);
-            linkedLists.add(copyList);
+//    private void dfs(TreeNode root, TreeNode p, TreeNode q) {
+//        if (root == null) return;
+//        list.add(root);
+//        map.put(root.val, root);
+//        if (root==p||root==q){
+//            LinkedList<TreeNode> copyList = new LinkedList<>(list);
+//            linkedLists.add(copyList);
+//        }
+//        dfs(root.left, p, q);
+//        dfs(root.right, p, q);
+//        list.pollLast();
+//    }
+
+    private boolean dfs(TreeNode root, TreeNode p, TreeNode q) {
+        if (root == null) {
+            return false;
         }
-        dfs(root.left, p, q);
-        dfs(root.right, p, q);
-        list.pollLast();
+        boolean left = dfs(root.left, p, q);
+        boolean right = dfs(root.right, p, q);
+        if ((left && right) || ((left || right) && (root.val == p.val || root.val == q.val))) {
+            this.res = root;
+        }
+        return root.val == p.val || root.val == q.val || left || right;
+
     }
 
 }