Solution (100%) to GenomicRangeQuery problem on Codility (https://codility.com/programmers/task/genomic_range_query/)

GenomicRangeQuery.java

/*
 * I WAS ONLY CAPABLE OF FINDING AN O(N*M) SOLUTION
 *
 * THE O(N+M) SOLUTION PRESENTED HERE IS BASED ON:
 * http://csharplabtests.blogspot.co.il/2015/06/codility-lesson-3-genomicrangequery.html
 */
 
class Solution
{
    public int[] solution(String S, int[] P, int[] Q)
    {
        int N = S.length();
        int[][] count = new int[N + 1][4];
        
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j < 4; j++)
            {
                count[i + 1][j] = count[i][j];
            }
            
            switch (S.charAt(i))
            {
                case 'A':
                    count[i + 1][0]++;
                    break;
                
                case 'C':
                    count[i + 1][1]++;
                    break;
                    
                case 'G':
                    count[i + 1][2]++;
                    break;
                
                case 'T':
                    count[i + 1][3]++;
                    break;
            }
        }
        
        int M = P.length;
        int[] results = new int[M];
        
        for (int i = 0; i < M; i++)
        {
            int i0 = P[i];
            int i1 = Q[i];
            
            for (int j = 0; j < 4; j++)
            {
                if (count[i1 + 1][j] - count[i0 + 0][j] > 0)
                {
                    results[i] = j + 1;
                    break;
                }
            }
        }
        
        return results;
    }
}