Anonymous inner classes create generic instances that display the dec… (#627)

* Anonymous inner classes create generic instances that display the declared type

* Update TreeNode.java

* Update binary_tree_bfs.java

* Update graph_bfs.java

---------

Co-authored-by: zongjianwei <zongjianwei@meituan.com>
Co-authored-by: Yudong Jin <krahets@163.com>

codes/java/chapter_graph/graph_bfs.java

@@ -16,9 +16,11 @@ public class graph_bfs {
         // 顶点遍历序列
         List<Vertex> res = new ArrayList<>();
         // 哈希表，用于记录已被访问过的顶点
-        Set<Vertex> visited = new HashSet<>() {{ add(startVet); }};
+        Set<Vertex> visited = new HashSet<>();
+        visited.add(startVet);
         // 队列用于实现 BFS
-        Queue<Vertex> que = new LinkedList<>() {{ offer(startVet); }};
+        Queue<Vertex> que = new LinkedList<>();
+        que.offer(startVet);
         // 以顶点 vet 为起点，循环直至访问完所有顶点
         while (!que.isEmpty()) {
             Vertex vet = que.poll(); // 队首顶点出队

codes/java/chapter_tree/binary_tree_bfs.java

@@ -13,7 +13,8 @@ public class binary_tree_bfs {
     /* 层序遍历 */
     static List<Integer> levelOrder(TreeNode root) {
         // 初始化队列，加入根节点
-        Queue<TreeNode> queue = new LinkedList<>() {{ add(root); }};
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.add(root);
         // 初始化一个列表，用于保存遍历序列
         List<Integer> list = new ArrayList<>();
         while (!queue.isEmpty()) {

codes/java/utils/TreeNode.java

@@ -26,7 +26,8 @@ public class TreeNode {
             return null;
 
         TreeNode root = new TreeNode(list.get(0));
-        Queue<TreeNode> queue = new LinkedList<>() {{ add(root); }};
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.add(root);
         int i = 0;
         while (!queue.isEmpty()) {
             TreeNode node = queue.poll();
@@ -51,7 +52,7 @@ public class TreeNode {
         List<Integer> list = new ArrayList<>();
         if (root == null)
             return list;
-        Queue<TreeNode> queue = new LinkedList<>() {{ add(root); }};
+        Queue<TreeNode> queue = new LinkedList<TreeNode>() {{ add(root); }};
         while (!queue.isEmpty()) {
             TreeNode node = queue.poll();
             if (node != null) {