/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main(String[] args) {
		int [] input = {1, 0, 0, 1, 0, 0, 1,1,1,1, 0,1};
		System.out.println(findMaxNumberOfOnes(input,0, input.length-1));
	}
 
	private static int findMaxNumberOfOnes(int[] input, int i, int j) {		
		if (i==j)
			return 1;
		int option1 = input[i] + findMaxNumberOfOnes(input, i+1, j);
		int option2 = count(input , i , j, true);
		int option3 = count(input, i, j, false);
		int option4 =findMaxNumberOfOnes(input, i, j-1) +input[j]; 
		return Math.max(option1, Math.max(option2,Math.max(option3,option4)));
	}
 
	private static int count(int[] input, int i, int j, boolean flipped) {
		int a = flipped?0:1;
		int count = 0;
		while (i<=j){
			count += (input[i++]==a)?1:0;
		}
		return count;
	}
}

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