Java代码
import java.util.*;
class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int[] q = new int[n];
for (int i = 0; i < n; i++) q[i] = sc.nextInt();
int N = 100010;
int[] s = new int[N];
int res = 0;
for (int i = 0, j = 0; i < n; i++) {
s[q[i]]++;
while (s[q[i]] > 1) {
s[q[j]]--;
j++;
}
res = Math.max(res, i - j + 1);
}
System.out.println(res);
}
}