Problem:
Score : 700 points

Problem Statement

Given is a sequence of N digits a_1a_2\ldots a_N, where each element is 1, 2, or 3.
Let x_{i,j} defined as follows:

x_{1,j} := a_j \quad (1 \leq j \leq N)

x_{i,j} := | x_{i-1,j} - x_{i-1,j+1} | \quad (2 \leq i \leq N and 1 \leq j \leq N+1-i)

Find x_{N,1}.

Constraints

2 \leq N \leq 10^6

a_i = 1,2,3 (1 \leq i \leq N)

Input

Input is given from Standard Input in the following format:

N
a_1a_2\ldotsa_N

Output

Print x_{N,1}.

Sample Input 1

4
1231

Sample Output 1

1

x_{1,1},x_{1,2},x_{1,3},x_{1,4} are respectively 1,2,3,1.

x_{2,1},x_{2,2},x_{2,3} are respectively |1-2| = 1,|2-3| = 1,|3-1| = 2.

x_{3,1},x_{3,2} are respectively |1-1| = 0,|1-2| = 1.

Finally, x_{4,1} = |0-1| = 1, so the answer is 1.

Sample Input 2

10
2311312312

Sample Output 2

0

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)



import java.util.Scanner;

public class Main {

	public static void main(String[] args) 
	{
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String s = sc.next();
		int[] a = new int[n];
		boolean d1 = false;
		int[] d = new int[n-1];
		for(int i = 0; i < s.length(); i++)
		{
			a[i] = s.charAt(i)-'0';
			if(i>0)
			{
				d[i-1] = a[i]-a[i-1];
				if(d[i-1]<0)d[i-1]*=-1;
				if(d[i-1] == 1)d1 = true;
			}
		}
		int m = n-1, t1 = 0, t2 = 0;
		
		for(int take = 0; take <= m-1; take++)
		{ //(m-1) C take 0
			int nn = m-1;
			boolean odd = ((nn) & ((nn)-take)) <= 0;
			odd = (take & (nn-take)) <= 0;
			if(d[take] == 1 && odd)t1++;
			if(d[take] == 2 && odd)t2++;
		}
		
		t1 = t1%2;
		t2 = t2%2;
		if(t1<0)t1+=2;if(t2<0)t2+=2;
		if(t1 == 0 && t2 == 0)
			System.out.println(0);
		else if(t2 == 1 && t1 == 0)
			if(!d1) System.out.println(2);
			else System.out.println(0);
		else System.out.println(1);
		
	}

}