由于超时,我的第一次尝试通过了除最后一个之外的所有测试用例.
在未能提出更高效的算法之后,我通过使用StringBuilder而不是直接连接字符串来改进代码.这使得运行时间从5秒到3.5秒不等.

我的问题是,还有其他方法可以改善运行时间吗？
谢谢.

以下是我的代码.

public class Solution {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int N = scanner.nextInt();
        scanner.nextLine();

        int[] oriNum = new int[N];        
        String[] oriStr = new String[N];
        int[] count = new int[100];
        int[] indices = new int[100];
        int[] output = new int[N];

        // save the originals and the count array
        for (int i = 0; i < N; i++) {
            oriNum[i] = scanner.nextInt();
            oriStr[i] = scanner.nextLine().trim();
            count[oriNum[i]]++;
        }

        // accumulate the count array
        indices[0] = 0;
        for (int i = 1; i < 100; i++) {
            indices[i] = indices[i-1] + count[i-1];
        }

        // output order
        for (int i = 0; i < N; i++) {
            int num = oriNum[i];
            output[indices[num]++] = i;
        }

        int bar = N/2;
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < N; i++) {            
            int index = output[i];
            if (index < bar) 
                sb.append("- ");
            else 
                sb.append(oriStr[index]+ " ");
        }
        System.out.println(sb.toString());
    }
}