Create 0127-word-ladder.go

Accepted submission: _https://leetcode.com/submissions/detail/871401854/_

go/0127-word-ladder.go

@@ -0,0 +1,47 @@
+func ladderLength(beginWord string, endWord string, wordList []string) int {
+    if !contains(wordList, endWord) {
+        return 0
+    }
+
+    nei := make(map[string][]string)
+    wordList = append(wordList, beginWord)
+    for _, word := range wordList {
+        for j := 0; j < len(word); j++ {
+            pattern := word[:j] + "*" + word[j + 1:]
+            nei[pattern] = append(nei[pattern], word)
+        }
+    }
+
+    visit := map[string]bool{beginWord: true}
+    q := []string{beginWord}
+    res := 1
+    for len(q) != 0 {
+        for tmp := len(q); tmp > 0; tmp-- {
+            word := q[0]
+            q = q[1:]
+            if word == endWord {
+                return res
+            }
+            for j := 0; j < len(word); j++ {
+                pattern := word[:j] + "*" + word[j + 1:]
+                for _, neiWord := range nei[pattern] {
+                    if !visit[neiWord] {
+                        visit[neiWord] = true
+                        q = append(q, neiWord)
+                    }
+                }
+            }
+        }
+        res += 1
+    }
+    return 0
+}
+
+func contains(s []string, word string) bool {
+    for _, element := range s {
+        if element == word {
+            return true
+        }
+    }
+    return false
+}