Question

我是Java的初学者。您能帮我找到给定数组中所有最大的字符串吗？

String[] allLongestStrings(String[] a) {
List<String> newArray = new ArrayList<String>();
String max = a[0];
for( int i = 0; i < a.length; i++){
    int sum = max.compareTo(a[i]);
    if( sum < 0) max = a[i];
}
for( int i = 0; i < a.length; i++){
    int b = max.compareTo(a[i]);
    if (b == 0) newArray.add(a[i]);
}
String[] stringArray = newArray.toArray(new String[0]);
return stringArray;

}

Answer 1

快速解答：

String[] allLongestStrings(String[] arr) {
    int longest = Arrays.stream(arr)
            .mapToInt(String::length)
            .max()
            .orElse(-1);

    return Arrays.stream(arr)
            .filter(s -> s.length() == longest)
            .toArray(String[]::new);
}

详细的答案有两种方式：

public static void main(String[] args) {
    String[] arr = new String[4];
    arr[0] = "cat";
    arr[1] = "mouse";
    arr[2] = "goose";
    arr[3] = "owl";

    String[] resultJava8 = allLongestStringsJava8(arr);
    String[] resultTraditionalWay = allLongestStringsTraditionalWay(arr);
}

static String[] allLongestStringsJava8(String[] arr) {
    int longest = Arrays.stream(arr)
            .mapToInt(String::length)
            .max()
            .orElse(-1);

    return Arrays.stream(arr)
            .filter(s -> s.length() == longest)
            .toArray(String[]::new);
}

static String[] allLongestStringsTraditionalWay(String[] arr) {
    Set<String> result = new HashSet<>(); //or use a LinkedList if there can be same strings
    int longestLength = 0;
    for (String s : arr) {
        if (s.length() < longestLength)
            continue;
        if (s.length() > longestLength)
            result.clear();
        result.add(s);
        longestLength = s.length();
    }
    return result.toArray(new String[0]);
}

Answer 2

您可以使用以下代码：

public static void main(String[] args) {
        String[] a = new String[] {"ab", "abc", "a", "def"};
        int maxLength = Arrays.stream(a).max(Comparator.comparing(s -> s.length())).get().length();
        System.out.println(Arrays.stream(a).filter(str -> str.length() == maxLength).collect(Collectors.toList()));
    }

输出：

[abc, def]

所有最长的字符串

2 个答案: