シャッフル

import java.util.ArrayList;
import java.util.Collections;

public class Shuffle{
    public static void main(String[] args){
        int N = 100;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i = 1 ; i <= N ; i++) {
            list.add(i);
        }

        Collections.shuffle(list);

        System.out.println(list);
    }
}