leetcode-go/medium/211.add-and-search-word-data-structure-design.go

type Node struct {
	IsKey    bool
	Children *[26]Node
}

type WordDictionary struct {
	Root *Node
}

/** Initialize your data structure here. */
func Constructor() WordDictionary {
	return WordDictionary{&Node{}}
}

/** Adds a word into the data structure. */
func (this *WordDictionary) AddWord(word string) {
	curr := this.Root
	for i := range word {
		if curr.Children == nil {
			curr.Children = &[26]Node{}
		}
		curr = &curr.Children[int(word[i]-'a')]
	}
	curr.IsKey = true
}

/** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
func (this *WordDictionary) Search(word string) bool {
	return this.search(word, 0, this.Root)
}

func (this *WordDictionary) search(word string, i int, node *Node) bool {
	if i == len(word) {
		return node.IsKey
	} else if node.Children == nil {
		return false
	}
	if word[i] != '.' {
		return this.search(word, i+1, &node.Children[int(word[i]-'a')])
	}
	for j := 0; j < 26; j++ {
		if this.search(word, i+1, &node.Children[j]) {
			return true
		}
	}
	return false
}

/**
 * Your WordDictionary object will be instantiated and called as such:
 * obj := Constructor();
 * obj.AddWord(word);
 * param_2 := obj.Search(word);
 */