java - 查找重复的单词

Question

我有这个任务需要做

Write a method that takes a String parameter. If the String has a double letter (i.e. contains the same letter twice in a row) then it should return true. Otherwise, it should return false.

This method must be named hasRepeat() and have a String parameter. This method must return a boolean.

但是，当我 checkin 代码时，我未通过一些测试。

它表示，当没有重复的字母时，它不会返回 false。

这是我的代码:

public static boolean hasRepeat(String word) {
    for (int i = 0; i < word.length(); i++) {
        for (int j = i + 1; j < word.length(); j++) {
            if (word.substring(i, i + 1).equals(word.substring(i, j))) {
                return true;
            }
        }
    }
    return false;
}

Answer 1

不需要嵌套循环。我们所要做的就是检查当前字符是否等于前一个:

public static boolean hasRepeat(String word) 
{
   // hasRepeat is a public method; we shoud be ready for any input
   if (word == null)
       return false;

   // here we start from 1: there's no previous char for charAt(0)
   for (int i = 1; i < word.length(); ++i)
     if (word.charAt(i - 1) == word.charAt(i))
       return true;

   return false;
}