java – 找不到sort(int [],>)的合适方法

例如,给定[3,30,34,5,9],最大形成数为9534330.

注意：结果可能非常大,因此您需要返回一个字符串而不是整数.

public class Solution {
    public String largestNumber(int[] num) {
        Arrays.sort(num,new java.util.Comparator<Integer>() {
            @Override
            public int compare(Integer a,Integer b) {
                String s1 = String.valueOf(a),s2 = String.valueOf(b);
                return Integer.parseInt(s1 + s2) - Integer.parseInt(s2 + s1);
            }
        });
        StringBuilder builder = new StringBuilder();
        for (int i = num.length - 1; i >= 0; i--)   builder.append(num[i]);
        return builder.toString();
    }
}

结果：第3行：错误：没有为sort(int [],< anonymous Comparator< Integer>>)找到合适的方法

有谁知道如何修改它？谢谢！

感谢您的所有详细解答,我已将我的代码修改为

public String largestNumber(int[] num) {
    int N = num.length;
    String[] aux = new String[N];
    for (int i = 0; i < N; i++) aux[i] = String.valueOf(num[i]); // int[] -> String[]
    Arrays.sort(aux,new Comparator<String>() {
        @Override
        public int compare(String a,String b) {
            return (int) (Long.parseLong(a + b) - Long.parseLong(b + a));  // note the overflow of int,max + max
        }
    });
    StringBuilder builder = new StringBuilder();
    for (int i = N - 1; i >= 0; i--)    builder.append(aux[i]);
    int sub = 0;
    for ( ; sub < builder.length() - 1 && builder.charAt(sub) == '0'; sub++);
    return builder.substring(sub).toString();
}

我仍在努力寻找避免使用额外空间的方法.