1 func binarySearch(nodes []*node, word Text) (int, bool) {
2 start := 0
3 end := len(nodes) - 1
4
5 // 特例：
6 if len(nodes) == 0 {
7 // 当slice为空时，插入第一位置
8 return 0, false
9 }
10 compareWithFirstWord := bytes.Compare(word, nodes[0].word)
11 if compareWithFirstWord < 0 {
12 // 当要查找的元素小于首元素时，插入第一位置
13 return 0, false
14 } else if compareWithFirstWord == 0 {
15 // 当首元素等于node时
16 return 0, true
17 }
18 compareWithLastWord := bytes.Compare(word, nodes[end].word)
19 if compareWithLastWord == 0 {
20 // 当尾元素等于node时
21 return end, true
22 } else if compareWithLastWord > 0 {
23 // 当尾元素小于node时
24 return end + 1, false
25 }
26
27 // 二分
28 current := end / 2
29 for end-start > 1 {
30 compareWithCurrentWord := bytes.Compare(word, nodes[current].word)
31 if compareWithCurrentWord == 0 {
32 return current, true
33 } else if compareWithCurrentWord < 0 {
34 end = current
35 current = (start + current) / 2
36 } else {
37 start = current
38 current = (current + end) / 2
39 }
40 }
41 return end, false
42 }
