Some random problem I found in a WhatsApp group

FacebookQuestion.java

public class FacebookProblem {

    public static void main(String[] args) {
        // TODO code application logic here
        int A[][] = {
            {5, 4, 4},
            {4, 3, 4},
            {3, 2, 4},
            {2, 2, 2},
            {3, 3, 4},
            {1, 4, 4},
            {4, 1, 1}
        };
        int answer = solution(A);
        System.out.println(answer);
    }
    public static int solution(int A[][]) {
        final int INVALID = 1000000009;
        int pointer = 2;
        int dp[][] = new int[A.length][A[0].length];
        dp[0][0] = 1;
        int last = A[0].length - 1, max = -1;
        for (int i = 0; i < A.length; i++) {
            for (int j = 0; j < A[i].length; j++) {
                int down,right;
                down =(i+1 < A.length) ? A[i+1][j] : INVALID;
                right = (j+1 <= last) ? A[i][j+1] : INVALID;
                
                if (dp[i][j] > 0) {
                    if (A[i][j] == right) dp[i][j+1] = dp[i][j];
                    if (A[i][j] == down) dp[i+1][j] = dp[i][j];
                } else {
                    dp[i][j] = pointer++;
                    if (A[i][j] == right) {
                        if (dp[i][j+1] > 0){ 
                            dp[i][j] = dp[i][j+1];
                            pointer--;
                        } else dp[i][j+1] = dp[i][j];
                    }
                    if (A[i][j] == down) dp[i+1][j] = dp[i][j];
                }
                max = Math.max(max, dp[i][j]);
            }
        }
        return max;
    }
}