java - 二进制搜索字符串数组

Question

如何对字符串数组进行二分查找排序。在下面，我的索引总是收到一个负数，而不是正确的索引。请帮忙？如果单词不在数组中，则应返回 -1。

  public static int binary (String [] theword, String a) {
    int index = -1;
        Arrays.sort(theword);
        Arrays.toString(theword);
        index = Arrays.binarySearch(theword, a);
    return index;

}   

Answer 1

有效，见下文

public static void main(String... args) {

    String words[] = { "abc3", "abc2", "abc1", "abc4" };

    Arrays.sort(words);
    System.out.println(Arrays.toString(words));
    {
        String word = "abc3";
        int index = Arrays.binarySearch(words, word);
        index = index >= 0 ? index : -1;
        System.out.println(word + " = " + index);
    }
    {
        String word = "abc11";
        int index = Arrays.binarySearch(words, word);
        index = index >= 0 ? index : -1;
        System.out.println(word + " = " + index);
    }
}

输出

[abc1, abc2, abc3, abc4]
abc3 = 2
abc11 = -1

当您需要原始数组的索引时，您返回排序后数组的索引。