http://codeforces.com/contest/978/problem/A
解题思路:
1.删掉重复的元素,只留下序列中不重复的最右边的元素
2.逆向搜一遍,把第一次遇到的元素入栈
3.依次出栈就是答案
import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int[] ele = new int[100];
for(int i = 1;i <= n;i++) {
ele[i] = sc.nextInt();
}
Stack<Integer> s = new Stack<>();
for(int i = n;i >= 1;i--) {
if(s.contains(ele[i])) //出现过的跳过
continue;
else
s.push(ele[i]); //没出现过的入栈
}
System.out.println(s.size());
while (!s.empty()) {
System.out.print(s.peek() + " ");
s.pop();
}
}
}