11054 가장 긴 바이토닉 부분 수열

import java.io.IOException;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.StringTokenizer;
public class main {
	static int[] arr;
	static int[] dp;
	static int[] dp2;
	static int N;
	static int count=0;
	public static void main(String[] args) throws IOException {
    
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		
		N = Integer.parseInt(br.readLine());
		arr = new int[N+1];
		dp = new int[N+1];
		dp2 = new int[N+1];	
		StringTokenizer st = new StringTokenizer(br.readLine()," ");
		for(int i=1; i<=N; i++) {
			arr[i]=Integer.parseInt(st.nextToken());
			dp[i]=1;
			dp2[i]=1;
		}
		
		for(int i=1; i<=N; i++) {
			for(int j=1; j<i; j++) {
				if(arr[i]>arr[j]) dp[i] = Math.max(dp[i],dp[j]+1);
			}
		}
		
		for(int i=N; i>=1; i--) {
			for(int j=N; j>i; j--) {
				if(arr[i]>arr[j]) dp2[i] = Math.max(dp2[i],dp2[j]+1);
			}
		}
		
		int max=Integer.MIN_VALUE;
		
		for(int i=1;i<=N;i++) {
			max=Math.max(max,dp[i]+dp2[i]);
		}
		
		bw.write(max-1+"\n");
		bw.flush();
		bw.close();
		
    }
}

계속 틀렸다해서 그냥 풀이봤따 ! ^^

그냥 배열 하나 더만들어서 합쳐버리네요,, 천재들;;;;;;;;;;;;;;;;;;;

이게 두개 더해주는거니까 마지막에 1빼줘야한다