首先介绍几个概念 root 和 successor， root 后面拼接一个单词可以形成一个长单词，该长单词被称为 successor。举个例子， root 为 an， 拼接单词 other 形成 another， another 就是 successor。

现在给出一个包含多个 root 的字典数组和一个句子。请将句子中的 successor 替换成 root。 如果 successor 有多个 root， 则用最短的 root 替换。

原题

In English, we have a concept called root, which can be followed by some other words to form another longer word - let’s call this word successor. For example, the root an, followed by other, which can form another word another.

Now, given a dictionary consisting of many roots and a sentence. You need to replace all the successor in the sentence with the root forming it. If a successor has many roots can form it, replace it with the root with the shortest length.

You need to output the sentence after the replacement.

Example 1:

Input: dict = ["cat", "bat", "rat"]
sentence = "the cattle was rattled by the battery"
Output: "the cat was rat by the bat"

Note:

• The input will only have lower-case letters
• 1 <= dict words number <= 1000
• 1 <= sentence words number <= 1000
• 1 <= root length <= 100
• 1 <= sentence words length <= 1000

分析

如题所述，目的是将句子中的单词（也就是 successor）用其 root 替换。

1. 根据空格将句子分离为一个单词数组
2. 将单词逐个寻找其 root，有则替换，无则忽略
3. 将替换后的单词数组，用空格拼接成新句子返回

另外需要注意的是，要找到最短的 root 进行替换。

实现

完整代码和测试已托管在 go-algorithm。

func replaceWords(dict []string, sentence string) string {
	words := strings.Split(sentence, " ")

	for i := 0; i < len(words); i++ {
		for _, v := range dict {
			if len(words[i]) >= len(v) && words[i][:len(v)] == v {
				// in order to find the shortest root, doesn't break on here
				words[i] = v
			}
		}
	}

	return strings.Join(words, " ")
}