添加与搜索单词

type WordDictionary struct {
	children map[rune]*WordDictionary
	isWord   bool
}

/** Initialize your data structure here. */
func Constructor() WordDictionary {
	return WordDictionary{children: make(map[rune]*WordDictionary)}
}

/** Adds a word into the data structure. */
func (this *WordDictionary) AddWord(word string) {
	parent := this
	for _, ch := range word {
		if child, ok := parent.children[ch]; ok {
			parent = child
		} else {
			newChild := &WordDictionary{children: make(map[rune]*WordDictionary)}
			parent.children[ch] = newChild
			parent = newChild
		}
	}
	parent.isWord = 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 {
	parent := this
	for i, ch := range word {
		if rune(ch) == '.' {
			isMatched := false
			for _, v := range parent.children {
				if v.Search(word[i+1:]) {
					isMatched = true
				}
			}
			return isMatched
		} else if _, ok := parent.children[rune(ch)]; !ok {
			return false
		}
		parent = parent.children[rune(ch)]
	}
	return len(parent.children) == 0 || parent.isWord
}

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

func main() {
    // 1. 主例
    //    输入：mode="add-search-word", words=["bad","dad","mad"]
    //    期望：search(".ad") true。
    //
    // 2. 失败 / 未命中
    //    检查：重复 add 同词要处理或允许。
    //
    // 3. 边界
    //    空输入、单元素、最小合法规模，以及答案恰好落在边界的情况。
    //
    // 4. 迁移
    //    LC208 Trie；LC212 单词搜索
}