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_dynamic_programming/climbing_stairs_backtrack.swift

@@ -22,7 +22,7 @@ func backtrack(choices: [Int], state: Int, n: Int, res: inout [Int]) {
 
 /* 爬楼梯：回溯 */
 func climbingStairsBacktrack(n: Int) -> Int {
-    let choices = [1, 2] // 可选择向上爬 1 或 2 阶
+    let choices = [1, 2] // 可选择向上爬 1 阶或 2 阶
     let state = 0 // 从第 0 阶开始爬
     var res: [Int] = []
     res.append(0) // 使用 res[0] 记录方案数量