feat: Revised the book (#978)

* Sync recent changes to the revised Word.

* Revised the preface chapter

* Revised the introduction chapter

* Revised the computation complexity chapter

* Revised the chapter data structure

* Revised the chapter array and linked list

* Revised the chapter stack and queue

* Revised the chapter hashing

* Revised the chapter tree

* Revised the chapter heap

* Revised the chapter graph

* Revised the chapter searching

* Reivised the sorting chapter

* Revised the divide and conquer chapter

* Revised the chapter backtacking

* Revised the DP chapter

* Revised the greedy chapter

* Revised the appendix chapter

* Revised the preface chapter doubly

* Revised the figures

codes/swift/chapter_stack_and_queue/linkedlist_deque.swift

@@ -38,7 +38,7 @@ class LinkedListDeque {
     /* 入队操作 */
     private func push(num: Int, isFront: Bool) {
         let node = ListNode(val: num)
-        // 若链表为空，则令 front, rear 都指向 node
+        // 若链表为空，则令 front 和 rear 都指向 node
         if isEmpty() {
             front = node
             rear = node