fix build

Author: fishercoder1534

Diff for: src/main/java/com/fishercoder/solutions/_426.java

@@ -41,14 +41,14 @@ private static class Node {
         public Node() {
         }
 
-        public Node(int _val) {
-            val = _val;
+        public Node(int val) {
+            this.val = val;
         }
 
-        public Node(int _val, Node _left, Node _right) {
-            val = _val;
-            left = _left;
-            right = _right;
+        public Node(int val, Node left, Node right) {
+            this.val = val;
+            this.left = left;
+            this.right = right;
         }
     }
 }