LeetCode - Replace Words

Question Definition

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:

1. The input will only have lower-case letters.
2. 1 <= dict words number <= 1000
3. 1 <= sentence words number <= 1000
4. 1 <= root length <= 100
5. 1 <= sentence words length <= 1000

   Java Solution

   public String replaceWords(List<String> dict, String sentence) {
    Set<String> set = new HashSet<>(dict);
    StringBuilder sb = new StringBuilder();
    for(String s : sentence.split(" ")){
        int i = 1;
        for(; i <= s.length(); i++){
            if(set.contains(s.substring(0, i))){
                sb.append(s.substring(0, i));
                sb.append(" ");
                break;
            }
        }
        if(i == s.length() + 1){
            sb.append(s);
            sb.append(" ");
        }
    }
    return sb.toString().trim();
   }