1888. Minimum Number of Flips to Make the Binary String Alternating

public class Solution
{
    public int MinFlips(string s)
    {
        int n = s.Length;
        // count[0][0] := the number of 0s in the even indices
        // count[0][1] := the number of 0s in the odd indices
        // count[1][0] := the number of 1s in the even indices
        // count[1][1] := the number of 1s in the odd indices
        int[,] count = new int[2, 2];

        for (int i = 0; i < n; ++i)
            count[s[i] - '0', i % 2]++;

        // min(make all 0s in the even indices + make all 1s in the odd indices,
        //     make all 1s in the even indices + make all 0s in the odd indices)
        int ans = Math.Min(count[1, 0] + count[0, 1], count[0, 0] + count[1, 1]);

        for (int i = 0; i < n; ++i)
        {
            count[s[i] - '0', i % 2]--;
            count[s[i] - '0', (n + i) % 2]++;
            ans = Math.Min(ans, Math.Min(count[1, 0] + count[0, 1], count[0, 0] + count[1, 1]));
        }

        return ans;
    }
}