Format the Java codes with the Reat Hat extension.

.gitignore

@@ -13,3 +13,6 @@ docs/overrides/
 build/
 site/
 utils/
+
+# test script
+test.sh

codes/java/chapter_array_and_linkedlist/array.java

@@ -13,8 +13,7 @@ public class array {
     /* 随机返回一个数组元素 */
     static int randomAccess(int[] nums) {
         // 在区间 [0, nums.length) 中随机抽取一个数字
-        int randomIndex = ThreadLocalRandom.current().
-                          nextInt(0, nums.length);
+        int randomIndex = ThreadLocalRandom.current().nextInt(0, nums.length);
         // 获取并返回随机元素
         int randomNum = nums[randomIndex];
         return randomNum;

codes/java/chapter_computational_complexity/leetcode_two_sum.java

@@ -8,7 +8,6 @@ package chapter_computational_complexity;
 
 import java.util.*;
 
-
 public class leetcode_two_sum {
     /* 方法一：暴力枚举 */
     static int[] twoSumBruteForce(int[] nums, int target) {

codes/java/chapter_computational_complexity/space_complexity.java

@@ -52,7 +52,8 @@ public class space_complexity {
     /* 线性阶（递归实现） */
     static void linearRecur(int n) {
         System.out.println("递归 n = " + n);
-        if (n == 1) return;
+        if (n == 1)
+            return;
         linearRecur(n - 1);
     }
 
@@ -73,7 +74,8 @@ public class space_complexity {
 
     /* 平方阶（递归实现） */
     static int quadraticRecur(int n) {
-        if (n <= 0) return 0;
+        if (n <= 0)
+            return 0;
         // 数组 nums 长度为 n, n-1, ..., 2, 1
         int[] nums = new int[n];
         System.out.println("递归 n = " + n + " 中的 nums 长度 = " + nums.length);
@@ -82,7 +84,8 @@ public class space_complexity {
 
     /* 指数阶（建立满二叉树） */
     static TreeNode buildTree(int n) {
-        if (n == 0) return null;
+        if (n == 0)
+            return null;
         TreeNode root = new TreeNode(0);
         root.left = buildTree(n - 1);
         root.right = buildTree(n - 1);

codes/java/chapter_computational_complexity/time_complexity.java

@@ -81,7 +81,8 @@ public class time_complexity {
 
     /* 指数阶（递归实现） */
     static int expRecur(int n) {
-        if (n == 1) return 1;
+        if (n == 1)
+            return 1;
         return expRecur(n - 1) + expRecur(n - 1) + 1;
     }
 
@@ -97,13 +98,15 @@ public class time_complexity {
 
     /* 对数阶（递归实现） */
     static int logRecur(float n) {
-        if (n <= 1) return 0;
+        if (n <= 1)
+            return 0;
         return logRecur(n / 2) + 1;
     }
 
     /* 线性对数阶 */
     static int linearLogRecur(float n) {
-        if (n <= 1) return 1;
+        if (n <= 1)
+            return 1;
         int count = linearLogRecur(n / 2) +
                 linearLogRecur(n / 2);
         for (int i = 0; i < n; i++) {
@@ -114,7 +117,8 @@ public class time_complexity {
 
     /* 阶乘阶（递归实现） */
     static int factorialRecur(int n) {
-        if (n == 0) return 1;
+        if (n == 0)
+            return 1;
         int count = 0;
         // 从 1 个分裂出 n 个
         for (int i = 0; i < n; i++) {

codes/java/chapter_hashing/array_hash_map.java

@@ -12,6 +12,7 @@ import java.util.*;
 class Entry {
     public int key;
     public String val;
+
     public Entry(int key, String val) {
         this.key = key;
         this.val = val;
@@ -21,6 +22,7 @@ class Entry {
 /* 基于数组简易实现的哈希表 */
 class ArrayHashMap {
     private List<Entry> buckets;
+
     public ArrayHashMap() {
         // 初始化数组，包含 100 个桶
         buckets = new ArrayList<>();
@@ -39,7 +41,8 @@ class ArrayHashMap {
     public String get(int key) {
         int index = hashFunc(key);
         Entry pair = buckets.get(index);
-        if (pair == null) return null;
+        if (pair == null)
+            return null;
         return pair.val;
     }
 
@@ -95,7 +98,6 @@ class ArrayHashMap {
     }
 }
 
-
 public class array_hash_map {
     public static void main(String[] args) {
         /* 初始化哈希表 */

codes/java/chapter_heap/heap.java

@@ -9,7 +9,6 @@ package chapter_heap;
 import include.*;
 import java.util.*;
 
-
 public class heap {
     public static void testPush(Queue<Integer> heap, int val) {
         heap.offer(val); // 元素入堆

codes/java/chapter_heap/my_heap.java

@@ -41,9 +41,9 @@ class MaxHeap {
 
     /* 交换元素 */
     private void swap(int i, int j) {
-        int a = maxHeap.get(i), 
-            b = maxHeap.get(j),
-            tmp = a;
+        int a = maxHeap.get(i);
+        int b = maxHeap.get(j);
+        int tmp = a;
         maxHeap.set(i, b);
         maxHeap.set(j, tmp);
     }
@@ -111,7 +111,8 @@ class MaxHeap {
             if (r < size() && maxHeap.get(r) > maxHeap.get(ma))
                 ma = r;
             // 若节点 i 最大或索引 l, r 越界，则无需继续堆化，跳出
-            if (ma == i) break;
+            if (ma == i)
+                break;
             // 交换两节点
             swap(i, ma);
             // 循环向下堆化
@@ -127,7 +128,6 @@ class MaxHeap {
     }
 }
 
-
 public class my_heap {
     public static void main(String[] args) {
         /* 初始化大顶堆 */

codes/java/chapter_sorting/bubble_sort.java

@@ -40,7 +40,8 @@ public class bubble_sort {
                     flag = true; // 记录交换元素
                 }
             }
-            if (!flag) break;     // 此轮冒泡未交换任何元素，直接跳出
+            if (!flag)
+                break; // 此轮冒泡未交换任何元素，直接跳出
         }
     }
 

codes/java/chapter_sorting/merge_sort.java

@@ -38,7 +38,8 @@ public class merge_sort {
     /* 归并排序 */
     static void mergeSort(int[] nums, int left, int right) {
         // 终止条件
-        if (left >= right) return;       // 当子数组长度为 1 时终止递归
+        if (left >= right)
+            return;                      // 当子数组长度为 1 时终止递归
         // 划分阶段
         int mid = (left + right) / 2;    // 计算中点
         mergeSort(nums, left, mid);      // 递归左子数组

codes/java/chapter_sorting/radix_sort.java

@@ -47,7 +47,8 @@ public class radix_sort {
         // 获取数组的最大元素，用于判断最大位数
         int m = Integer.MIN_VALUE;
         for (int num : nums)
-            if (num > m) m = num;
+            if (num > m)
+                m = num;
         // 按照从低位到高位的顺序遍历
         for (int exp = 1; exp <= m; exp *= 10)
             // 对数组元素的第 k 位执行计数排序

codes/java/chapter_stack_and_queue/array_stack.java

@@ -11,6 +11,7 @@ import java.util.*;
 /* 基于数组实现的栈 */
 class ArrayStack {
     private ArrayList<Integer> stack;
+
     public ArrayStack() {
         // 初始化列表（动态数组）
         stack = new ArrayList<>();

codes/java/chapter_stack_and_queue/linkedlist_deque.java

@@ -13,6 +13,7 @@ class ListNode {
     int val; // 节点值
     ListNode next; // 后继节点引用（指针）
     ListNode prev; // 前驱节点引用（指针）
+
     ListNode(int val) {
         this.val = val;
         prev = next = null;

codes/java/chapter_tree/avl_tree.java

@@ -27,7 +27,8 @@ class AVLTree {
     /* 获取平衡因子 */
     public int balanceFactor(TreeNode node) {
         // 空节点平衡因子为 0
-        if (node == null) return 0;
+        if (node == null)
+            return 0;
         // 节点平衡因子 = 左子树高度 - 右子树高度
         return height(node.left) - height(node.right);
     }
@@ -98,7 +99,8 @@ class AVLTree {
 
     /* 递归插入节点（辅助方法） */
     private TreeNode insertHelper(TreeNode node, int val) {
-        if (node == null) return new TreeNode(val);
+        if (node == null)
+            return new TreeNode(val);
         /* 1. 查找插入位置，并插入节点 */
         if (val < node.val)
             node.left = insertHelper(node.left, val);
@@ -121,7 +123,8 @@ class AVLTree {
 
     /* 递归删除节点（辅助方法） */
     private TreeNode removeHelper(TreeNode node, int val) {
-        if (node == null) return null;
+        if (node == null)
+            return null;
         /* 1. 查找节点，并删除之 */
         if (val < node.val)
             node.left = removeHelper(node.left, val);
@@ -152,7 +155,8 @@ class AVLTree {
 
     /* 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） */
     private TreeNode getInOrderNext(TreeNode node) {
-        if (node == null) return node;
+        if (node == null)
+            return node;
         // 循环访问左子节点，直到叶节点时为最小节点，跳出
         while (node.left != null) {
             node = node.left;

codes/java/chapter_tree/binary_search_tree.java

@@ -25,7 +25,8 @@ class BinarySearchTree {
 
     /* 构建二叉搜索树 */
     public TreeNode buildTree(int[] nums, int i, int j) {
-        if (i > j) return null;
+        if (i > j)
+            return null;
         // 将数组中间节点作为根节点
         int mid = (i + j) / 2;
         TreeNode root = new TreeNode(nums[mid]);
@@ -41,11 +42,14 @@ class BinarySearchTree {
         // 循环查找，越过叶节点后跳出
         while (cur != null) {
             // 目标节点在 cur 的右子树中
-            if (cur.val < num) cur = cur.right;
+            if (cur.val < num)
+                cur = cur.right;
             // 目标节点在 cur 的左子树中
-            else if (cur.val > num) cur = cur.left;
+            else if (cur.val > num)
+                cur = cur.left;
             // 找到目标节点，跳出循环
-            else break;
+            else
+                break;
         }
         // 返回目标节点
         return cur;
@@ -54,49 +58,62 @@ class BinarySearchTree {
     /* 插入节点 */
     public TreeNode insert(int num) {
         // 若树为空，直接提前返回
-        if (root == null) return null;
+        if (root == null)
+            return null;
         TreeNode cur = root, pre = null;
         // 循环查找，越过叶节点后跳出
         while (cur != null) {
             // 找到重复节点，直接返回
-            if (cur.val == num) return null;
+            if (cur.val == num)
+                return null;
             pre = cur;
             // 插入位置在 cur 的右子树中
-            if (cur.val < num) cur = cur.right;
+            if (cur.val < num)
+                cur = cur.right;
             // 插入位置在 cur 的左子树中
-            else cur = cur.left;
+            else
+                cur = cur.left;
         }
         // 插入节点 val
         TreeNode node = new TreeNode(num);
-        if (pre.val < num) pre.right = node;
-        else pre.left = node;
+        if (pre.val < num)
+            pre.right = node;
+        else
+            pre.left = node;
         return node;
     }
 
     /* 删除节点 */
     public TreeNode remove(int num) {
         // 若树为空，直接提前返回
-        if (root == null) return null;
+        if (root == null)
+            return null;
         TreeNode cur = root, pre = null;
         // 循环查找，越过叶节点后跳出
         while (cur != null) {
             // 找到待删除节点，跳出循环
-            if (cur.val == num) break;
+            if (cur.val == num)
+                break;
             pre = cur;
             // 待删除节点在 cur 的右子树中
-            if (cur.val < num) cur = cur.right;
+            if (cur.val < num)
+                cur = cur.right;
             // 待删除节点在 cur 的左子树中
-            else cur = cur.left;
+            else
+                cur = cur.left;
         }
         // 若无待删除节点，则直接返回
-        if (cur == null) return null;
+        if (cur == null)
+            return null;
         // 子节点数量 = 0 or 1
         if (cur.left == null || cur.right == null) {
             // 当子节点数量 = 0 / 1 时， child = null / 该子节点
             TreeNode child = cur.left != null ? cur.left : cur.right;
             // 删除节点 cur
-            if (pre.left == cur) pre.left = child;
-            else pre.right = child;
+            if (pre.left == cur)
+                pre.left = child;
+            else
+                pre.right = child;
         }
         // 子节点数量 = 2
         else {
@@ -113,7 +130,8 @@ class BinarySearchTree {
 
     /* 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） */
     public TreeNode getInOrderNext(TreeNode root) {
-        if (root == null) return root;
+        if (root == null)
+            return root;
         // 循环访问左子节点，直到叶节点时为最小节点，跳出
         while (root.left != null) {
             root = root.left;

codes/java/chapter_tree/binary_tree_dfs.java

@@ -15,7 +15,8 @@ public class binary_tree_dfs {
 
     /* 前序遍历 */
     static void preOrder(TreeNode root) {
-        if (root == null) return;
+        if (root == null)
+            return;
         // 访问优先级：根节点 -> 左子树 -> 右子树
         list.add(root.val);
         preOrder(root.left);
@@ -24,7 +25,8 @@ public class binary_tree_dfs {
 
     /* 中序遍历 */
     static void inOrder(TreeNode root) {
-        if (root == null) return;
+        if (root == null)
+            return;
         // 访问优先级：左子树 -> 根节点 -> 右子树
         inOrder(root.left);
         list.add(root.val);
@@ -33,7 +35,8 @@ public class binary_tree_dfs {
 
     /* 后序遍历 */
     static void postOrder(TreeNode root) {
-        if (root == null) return;
+        if (root == null)
+            return;
         // 访问优先级：左子树 -> 右子树 -> 根节点
         postOrder(root.left);
         postOrder(root.right);

codes/java/include/ListNode.java

@@ -6,9 +6,7 @@
 
 package include;
 
-/**
- * Definition for a singly-linked list node
- */
+/* Definition for a singly-linked list node */
 public class ListNode {
     public int val;
     public ListNode next;
@@ -17,11 +15,7 @@ public class ListNode {
         val = x;
     }
 
-    /**
-     * Generate a linked list with an array
-     * @param arr
-     * @return
-     */
+    /* Generate a linked list with an array */
     public static ListNode arrToLinkedList(int[] arr) {
         ListNode dum = new ListNode(0);
         ListNode head = dum;
@@ -32,12 +26,7 @@ public class ListNode {
         return dum.next;
     }
 
-    /**
-     * Get a list node with specific value from a linked list
-     * @param head
-     * @param val
-     * @return
-     */
+    /* Get a list node with specific value from a linked list */
     public static ListNode getListNode(ListNode head, int val) {
         while (head != null && head.val != val) {
             head = head.next;

codes/java/include/PrintUtil.java

@@ -8,7 +8,6 @@ package include;
 
 import java.util.*;
 
-
 class Trunk {
     Trunk prev;
     String str;
@@ -21,11 +20,7 @@ class Trunk {
 
 public class PrintUtil {
 
-    /**
-     * Print a matrix (Array)
-     * @param <T>
-     * @param matrix
-     */
+    /* Print a matrix (Array) */
     public static <T> void printMatrix(T[][] matrix) {
         System.out.println("[");
         for (T[] row : matrix) {
@@ -34,11 +29,7 @@ public class PrintUtil {
         System.out.println("]");
     }
 
-    /**
-     * Print a matrix (List)
-     * @param <T>
-     * @param matrix
-     */
+    /* Print a matrix (List) */
     public static <T> void printMatrix(List<List<T>> matrix) {
         System.out.println("[");
         for (List<T> row : matrix) {
@@ -47,10 +38,7 @@ public class PrintUtil {
         System.out.println("]");
     }
 
-    /**
-     * Print a linked list
-     * @param head
-     */
+    /* Print a linked list */
     public static void printLinkedList(ListNode head) {
         List<String> list = new ArrayList<>();
         while (head != null) {
@@ -64,18 +52,12 @@ public class PrintUtil {
      * The interface of the tree printer
      * This tree printer is borrowed from TECHIE DELIGHT
      * https://www.techiedelight.com/c-program-print-binary-tree/
-     * @param root
      */
     public static void printTree(TreeNode root) {
         printTree(root, null, false);
     }
 
-    /**
-     * Print a binary tree
-     * @param root
-     * @param prev
-     * @param isLeft
-     */
+    /* Print a binary tree */
     public static void printTree(TreeNode root, Trunk prev, boolean isLeft) {
         if (root == null) {
             return;
@@ -107,10 +89,7 @@ public class PrintUtil {
         printTree(root.left, trunk, false);
     }
 
-    /**
-     * Helper function to print branches of the binary tree
-     * @param p
-     */
+    /* Helper function to print branches of the binary tree */
     public static void showTrunks(Trunk p) {
         if (p == null) {
             return;
@@ -120,22 +99,14 @@ public class PrintUtil {
         System.out.print(p.str);
     }
 
-    /**
-     * Print a hash map
-     * @param <K>
-     * @param <V>
-     * @param map
-     */
+    /* Print a hash map */
     public static <K, V> void printHashMap(Map<K, V> map) {
         for (Map.Entry<K, V> kv : map.entrySet()) {
             System.out.println(kv.getKey() + " -> " + kv.getValue());
         }
     }
 
-    /**
-     * Print a heap (PriorityQueue)
-     * @param queue
-     */
+    /* Print a heap (PriorityQueue) */
     public static void printHeap(Queue<Integer> queue) {
         List<Integer> list = new ArrayList<>(queue);
         System.out.print("堆的数组表示：");

codes/java/include/TreeNode.java

@@ -8,9 +8,7 @@ package include;
 
 import java.util.*;
 
-/**
- * Definition for a binary tree node.
- */
+/* Definition for a binary tree node. */
 public class TreeNode {
     public int val; // 节点值
     public int height; // 节点高度
@@ -21,11 +19,7 @@ public class TreeNode {
         val = x;
     }
 
-    /**
-     * Generate a binary tree given an array
-     * @param list
-     * @return
-     */
+    /* Generate a binary tree given an array */
     public static TreeNode listToTree(List<Integer> list) {
         int size = list.size();
         if (size == 0)
@@ -36,12 +30,14 @@ public class TreeNode {
         int i = 0;
         while (!queue.isEmpty()) {
             TreeNode node = queue.poll();
-            if (++i >= size) break;
+            if (++i >= size)
+                break;
             if (list.get(i) != null) {
                 node.left = new TreeNode(list.get(i));
                 queue.add(node.left);
             }
-            if (++i >= size) break;
+            if (++i >= size)
+                break;
             if (list.get(i) != null) {
                 node.right = new TreeNode(list.get(i));
                 queue.add(node.right);
@@ -50,14 +46,11 @@ public class TreeNode {
         return root;
     }
 
-    /**
-     * Serialize a binary tree to a list
-     * @param root
-     * @return
-     */
+    /* Serialize a binary tree to a list */
     public static List<Integer> treeToList(TreeNode root) {
         List<Integer> list = new ArrayList<>();
-        if(root == null) return list;
+        if (root == null)
+            return list;
         Queue<TreeNode> queue = new LinkedList<>() {{ add(root); }};
         while (!queue.isEmpty()) {
             TreeNode node = queue.poll();
@@ -65,8 +58,7 @@ public class TreeNode {
                 list.add(node.val);
                 queue.add(node.left);
                 queue.add(node.right);
-            }
-            else {
+            } else {
                 list.add(null);
             }
         }

codes/java/include/Vertex.java

@@ -11,6 +11,7 @@ import java.util.*;
 /* 顶点类 */
 public class Vertex {
     public int val;
+
     public Vertex(int val) {
         this.val = val;
     }

codes/python/.gitignore

@@ -1,3 +1 @@
 __pycache__
-
-test_all.sh