package q211

type TrieNode struct {
	word bool
	next [26]*TrieNode
}

func (n *TrieNode) hasMatch(pattern string, offset int) bool {
	if n == nil {
		return false
	}
	if offset == len(pattern) {
		return n.word
	}

	c := pattern[offset]
	if c != '.' {
		return n.next[toIdx(c)].hasMatch(pattern, offset+1)
	}

	// Wildcard character
	for _, t := range n.next {
		if t != nil && t.hasMatch(pattern, offset+1) {
			return true
		}
	}

	return false
}

func toIdx(b byte) int8 { return int8(b - 'a') }

type WordDictionary struct{ root *TrieNode }

func Constructor() WordDictionary {
	return WordDictionary{
		root: &TrieNode{},
	}
}

func (d *WordDictionary) AddWord(word string) {
	curr := d.root
	for i := range len(word) {
		c := word[i]
		idx := toIdx(c)
		if curr.next[idx] == nil {
			curr.next[idx] = &TrieNode{}
		}
		curr = curr.next[idx]
	}
	curr.word = true
}

func (d *WordDictionary) Search(word string) bool {
	return d.root.hasMatch(word, 0)
}

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