Prefix sum with Hashmaps

public class Solution {
    public int FindMaxLength(int[] nums) {
        Dictionary<int, int> counts = new() 
        {
            {0, -1}
        };
        int count = 0;
        int answer = 0;

        for (int i = 0; i < nums.Length; i++)
        {
            if (nums[i] == 1)
                count++;
            else
                count--;
            
            if (counts.ContainsKey(count))
                answer = Math.Max(answer, i - counts[count]);
            else
                counts[count] = i;
        }

        return answer;
    }
}