add 2265

Author: fishercoder1534

Diff for: paginated_contents/algorithms/3rd_thousand/README.md

@@ -88,6 +88,7 @@
 | 2273 | [Find Resultant Array After Removing Anagrams](https://leetcode.com/problems/find-resultant-array-after-removing-anagrams/)                                                                   | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2273.java)                                       || Easy                                 ||
 | 2270 | [Number of Ways to Split Array](https://leetcode.com/problems/number-of-ways-to-split-array/)                                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2270.java)                                       || Medium                               ||
 | 2269 | [Find the K-Beauty of a Number](https://leetcode.com/problems/find-the-k-beauty-of-a-number/)                                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2269.java)                                       || Easy                                 ||
+| 2265 | [Count Nodes Equal to Average of Subtree](https://leetcode.com/problems/count-nodes-equal-to-average-of-subtree/)                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2265.java)                                       || Medium                               |Tree, DFS
 | 2264 | [Largest 3-Same-Digit Number in String](https://leetcode.com/problems/largest-3-same-digit-number-in-string/)                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2264.java)                                       || Easy                                 ||
 | 2260 | [Minimum Consecutive Cards to Pick Up](https://leetcode.com/problems/minimum-consecutive-cards-to-pick-up/)                                                                                   | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2260.java)                                       || Medium                               ||
 | 2259 | [Remove Digit From Number to Maximize Result](https://leetcode.com/problems/remove-digit-from-number-to-maximize-result/)                                                                     | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2259.java)                                       || Easy                                 ||

Diff for: src/main/java/com/fishercoder/solutions/thirdthousand/_2265.java

@@ -0,0 +1,33 @@
+package com.fishercoder.solutions.thirdthousand;
+
+import com.fishercoder.common.classes.TreeNode;
+
+public class _2265 {
+    public static class Solution1 {
+        /**
+         * When it comes to process all subtrees first, and then process the root, it's a good candidate to use post-order traversal recursion.
+         * Credit: https://leetcode.com/problems/count-nodes-equal-to-average-of-subtree/editorial/
+         */
+
+        int count;
+
+        public int averageOfSubtree(TreeNode root) {
+            postOrder(root);
+            return count;
+        }
+
+        private int[] postOrder(TreeNode root) {
+            if (root == null) {
+                return new int[2];
+            }
+            int[] left = postOrder(root.left);
+            int[] right = postOrder(root.right);
+            int nodeSum = left[0] + right[0] + root.val;
+            int nodeCount = left[1] + right[1] + 1;
+            if (root.val == nodeSum / nodeCount) {
+                count++;
+            }
+            return new int[]{nodeSum, nodeCount};
+        }
+    }
+}

Diff for: src/test/java/com/fishercoder/thirdthousand/_2265Test.java

@@ -0,0 +1,29 @@
+package com.fishercoder.thirdthousand;
+
+import com.fishercoder.common.classes.TreeNode;
+import com.fishercoder.common.utils.TreeUtils;
+import com.fishercoder.solutions.thirdthousand._2265;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class _2265Test {
+    private static _2265.Solution1 solution1;
+    private static TreeNode root;
+
+    @BeforeEach
+    public void setup() {
+        solution1 = new _2265.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        root = TreeUtils.constructBinaryTree(Arrays.asList(4, 8, 5, 0, 1, null, 6));
+        TreeUtils.printBinaryTree(root);
+        assertEquals(5, solution1.averageOfSubtree(root));
+    }
+
+}