udpate 226 java, cheatsheet

yennanliu · Mar 10, 2024 · 15eb825 · 15eb825
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Showing 4 changed files with 89 additions and 13 deletions.
diff --git a/data/progress.txt b/data/progress.txt
@@ -1,4 +1,4 @@
-20240310: 213,217
+20240310: 213,217,226
 20240309: 207(again!!!),208,211(again),212
 20240308: 152,153(again),190,191,198,200,206(again)
 20240307: 139(again),141,143(again)

diff --git a/data/to_review.txt b/data/to_review.txt
@@ -1,4 +1,4 @@
-2024-05-04 -> ['213,217']
+2024-05-04 -> ['213,217,226']
 2024-05-03 -> ['207(again!!!),208,211(again),212']
 2024-05-02 -> ['152,153(again),190,191,198,200,206(again)']
 2024-05-01 -> ['139(again),141,143(again)']
@@ -9,7 +9,7 @@
 2024-04-24 -> ['39,48(again),49,53,54']
 2024-04-23 -> ['20,21,23,33(again)']
 2024-04-22 -> ['1,3,5,4,19']
-2024-04-13 -> ['213,217']
+2024-04-13 -> ['213,217,226']
 2024-04-12 -> ['207(again!!!),208,211(again),212']
 2024-04-11 -> ['152,153(again),190,191,198,200,206(again)']
 2024-04-10 -> ['139(again),141,143(again)']
@@ -20,27 +20,27 @@
 2024-04-03 -> ['39,48(again),49,53,54']
 2024-04-02 -> ['20,21,23,33(again)']
 2024-04-01 -> ['1,3,5,4,19']
-2024-03-31 -> ['213,217']
+2024-03-31 -> ['213,217,226']
 2024-03-30 -> ['207(again!!!),208,211(again),212']
 2024-03-29 -> ['152,153(again),190,191,198,200,206(again)']
 2024-03-28 -> ['139(again),141,143(again)']
 2024-03-27 -> ['121,124(again),125,128,133(again)']
 2024-03-26 -> ['100,102,104,105(again)']
 2024-03-25 -> ['73,76,79(again),91,25']
 2024-03-24 -> ['55(again),56,62,70']
-2024-03-23 -> ['213,217']
+2024-03-23 -> ['213,217,226']
 2024-03-22 -> ['207(again!!!),208,211(again),212']
 2024-03-21 -> ['152,153(again),190,191,198,200,206(again)', '39,48(again),49,53,54']
 2024-03-20 -> ['139(again),141,143(again)', '20,21,23,33(again)']
 2024-03-19 -> ['121,124(again),125,128,133(again)', '1,3,5,4,19']
-2024-03-18 -> ['213,217', '100,102,104,105(again)']
+2024-03-18 -> ['213,217,226', '100,102,104,105(again)']
 2024-03-17 -> ['207(again!!!),208,211(again),212', '73,76,79(again),91,25']
 2024-03-16 -> ['152,153(again),190,191,198,200,206(again)', '55(again),56,62,70']
-2024-03-15 -> ['213,217', '139(again),141,143(again)']
+2024-03-15 -> ['213,217,226', '139(again),141,143(again)']
 2024-03-14 -> ['207(again!!!),208,211(again),212', '121,124(again),125,128,133(again)']
-2024-03-13 -> ['213,217', '152,153(again),190,191,198,200,206(again)', '100,102,104,105(again)', '39,48(again),49,53,54']
-2024-03-12 -> ['213,217', '207(again!!!),208,211(again),212', '139(again),141,143(again)', '73,76,79(again),91,25', '20,21,23,33(again)']
-2024-03-11 -> ['213,217', '207(again!!!),208,211(again),212', '152,153(again),190,191,198,200,206(again)', '121,124(again),125,128,133(again)', '55(again),56,62,70', '1,3,5,4,19']
+2024-03-13 -> ['213,217,226', '152,153(again),190,191,198,200,206(again)', '100,102,104,105(again)', '39,48(again),49,53,54']
+2024-03-12 -> ['213,217,226', '207(again!!!),208,211(again),212', '139(again),141,143(again)', '73,76,79(again),91,25', '20,21,23,33(again)']
+2024-03-11 -> ['213,217,226', '207(again!!!),208,211(again),212', '152,153(again),190,191,198,200,206(again)', '121,124(again),125,128,133(again)', '55(again),56,62,70', '1,3,5,4,19']
 2024-03-10 -> ['207(again!!!),208,211(again),212', '152,153(again),190,191,198,200,206(again)', '139(again),141,143(again)', '100,102,104,105(again)']
 2024-03-09 -> ['152,153(again),190,191,198,200,206(again)', '139(again),141,143(again)', '121,124(again),125,128,133(again)', '73,76,79(again),91,25']
 2024-03-08 -> ['139(again),141,143(again)', '121,124(again),125,128,133(again)', '100,102,104,105(again)', '55(again),56,62,70', '39,48(again),49,53,54']

diff --git a/doc/cheatsheet/tree.md b/doc/cheatsheet/tree.md
@@ -759,6 +759,46 @@ class Solution(object):
         return root
 ```
 
+```java
+// java
+// DFS
+    // V0
+    // IDEA : DFS
+    public TreeNode invertTree(TreeNode root) {
+        if (root == null) {
+            return null;
+        }
+        /** NOTE !!!!
+         *
+         *   instead of calling invertTree and assign value to sub tree directly,
+         *   we need to CACHE invertTree result, and assign later
+         *   -> since assign directly will cause tree changed, and affect the other invertTree call
+         *
+         *   e.g. below is WRONG,
+         *      root.left = invertTree(root.right);
+         *      root.right = invertTree(root.left);
+         *
+         *   need to cache result
+         *
+         *       TreeNode left = invertTree(root.left);
+         *       TreeNode right = invertTree(root.right);
+         *
+         *   then assign to sub tree
+         *
+         *       root.left = right;
+         *       root.right = left;
+         */
+        TreeNode left = invertTree(root.left);
+        TreeNode right = invertTree(root.right);
+        root.left = right;
+        root.right = left;
+        /** NOTE !!!! below is WRONG */
+//        root.left = invertTree(root.right);
+//        root.right = invertTree(root.left);
+        return root;
+    }
+```
+
 ### 1-1-16) Get neighborhood node (for each node) from tree
 ```python
 # LC 863. All Nodes Distance K in Binary Tree

diff --git a/leetcode_java/src/main/java/LeetCodeJava/Tree/InvertBinaryTree.java b/leetcode_java/src/main/java/LeetCodeJava/Tree/InvertBinaryTree.java
@@ -11,8 +11,44 @@
 public class InvertBinaryTree {
 
     // V0
-    // IDEA : BFS
+    // IDEA : DFS
     public TreeNode invertTree(TreeNode root) {
+        if (root == null) {
+            return null;
+        }
+        /** NOTE !!!!
+         *
+         *   instead of calling invertTree and assign value to sub tree directly,
+         *   we need to CACHE invertTree result, and assign later
+         *   -> since assign directly will cause tree changed, and affect the other invertTree call
+         *
+         *   e.g. below is WRONG,
+         *      root.left = invertTree(root.right);
+         *      root.right = invertTree(root.left);
+         *
+         *   need to cache result
+         *
+         *       TreeNode left = invertTree(root.left);
+         *       TreeNode right = invertTree(root.right);
+         *
+         *   then assign to sub tree
+         *
+         *       root.left = right;
+         *       root.right = left;
+         */
+        TreeNode left = invertTree(root.left);
+        TreeNode right = invertTree(root.right);
+        root.left = right;
+        root.right = left;
+        /** NOTE !!!! below is WRONG */
+//        root.left = invertTree(root.right);
+//        root.right = invertTree(root.left);
+        return root;
+    }
+
+    // V0
+    // IDEA : BFS
+    public TreeNode invertTree_(TreeNode root) {
 
         if (root == null) {
             return null;
@@ -48,8 +84,8 @@ public TreeNode invertTree_2(TreeNode root) {
         if (root == null) {
             return null;
         }
-        TreeNode right = invertTree(root.right);
-        TreeNode left = invertTree(root.left);
+        TreeNode right = invertTree_2(root.right);
+        TreeNode left = invertTree_2(root.left);
         root.left = right;
         root.right = left;
         return root;