src/main/java/com/cool/hot100/binary_tree/Num543.java

@@ -11,20 +11,18 @@ package com.cool.hot100.binary_tree;
  */
 public class Num543 {
 
-    int max=0;
     public int diameterOfBinaryTree(TreeNode root) {
         if (root == null) return 0;
         int left = getTreeDeep(root.left);
         int right = getTreeDeep(root.right);
-        return Math.max(max,left+right);
+        return left + right;
     }
 
     private int getTreeDeep(TreeNode root) {
         if (root == null) return 0;
-        int left = getTreeDeep(root.left);
-        int right=getTreeDeep(root.right);
-        max = Math.max(max,left+right );
-        return Math.max(left,right)+1;
+        int res = getTreeDeep(root.left);
+        res = Math.max(res, getTreeDeep(root.right));
+        return res + 1;
     }
 
 }