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/go/chapter_searching/two_sum.go

@@ -7,7 +7,7 @@ package chapter_searching
 /* 方法一：暴力枚举 */
 func twoSumBruteForce(nums []int, target int) []int {
 	size := len(nums)
-	// 两层循环，时间复杂度 O(n^2)
+	// 两层循环，时间复杂度为 O(n^2)
 	for i := 0; i < size-1; i++ {
 		for j := i + 1; i < size; j++ {
 			if nums[i]+nums[j] == target {
@@ -20,9 +20,9 @@ func twoSumBruteForce(nums []int, target int) []int {
 
 /* 方法二：辅助哈希表 */
 func twoSumHashTable(nums []int, target int) []int {
-	// 辅助哈希表，空间复杂度 O(n)
+	// 辅助哈希表，空间复杂度为 O(n)
 	hashTable := map[int]int{}
-	// 单层循环，时间复杂度 O(n)
+	// 单层循环，时间复杂度为 O(n)
 	for idx, val := range nums {
 		if preIdx, ok := hashTable[target-val]; ok {
 			return []int{preIdx, idx}