0127.单词接龙 增加go语言的解法

0127.单词接龙 增加go语言的解法

problems/0127.单词接龙.md

@@ -158,6 +158,57 @@ class Solution:
         return 0
 ```
 ## Go 
+```go
+func ladderLength(beginWord string, endWord string, wordList []string) int {
+	wordMap, que, depth := getWordMap(wordList, beginWord), []string{beginWord}, 0
+	for len(que) > 0 {
+		depth++
+		qLen := len(que) // 单词的长度
+		for i := 0; i < qLen; i++ {
+			word := que[0]
+			que = que[1:] // 首位单词出队
+			candidates := getCandidates(word)
+			for _, candidate := range candidates {
+				if _, exist := wordMap[candidate]; exist { // 用生成的结果集去查询
+					if candidate == endWord {
+						return depth + 1
+					}
+					delete(wordMap, candidate) // 删除集合中的用过的结果
+					que = append(que, candidate) 
+				}
+			}
+		}
+	}
+	return 0
+}
+
+
+// 获取单词Map为后续的查询增加速度
+func getWordMap(wordList []string, beginWord string) map[string]int {
+	wordMap := make(map[string]int)
+	for i, word := range wordList {
+		if _, exist := wordMap[word]; !exist {
+			if word != beginWord {
+				wordMap[word] = i
+			}
+		}
+	}
+	return wordMap
+}
+
+// 用26个英文字母分别替换掉各个位置的字母，生成一个结果集
+func getCandidates(word string) []string {
+	var res []string
+	for i := 0; i < 26; i++ {
+		for j := 0; j < len(word); j++ {
+			if word[j] != byte(int('a')+i) {
+				res = append(res, word[:j]+string(int('a')+i)+word[j+1:])
+			}
+		}
+	}
+	return res
+}
+```
 
 ## JavaScript
 ```javascript