题目描述
java
样例
import java.io.*;
import java.util.Scanner;
import java.util.Set;
import java.util.HashSet;
public class Main {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
int n = Integer.parseInt(reader.readLine());
String[] strs1 = reader.readLine().split(" ");
Set<Integer> set = new HashSet<>();
int ans = 0;
for(int i = 0, j = 0; i < n ; i++) {
while(j < n && set.add(Integer.parseInt(strs1[j]))){
j++;
}
set.remove(Integer.parseInt(strs1[i]));
ans = Math.max(ans, j - i);
}
writer.write(ans+"");
writer.flush();
writer.close();
reader.close();
}
}
```