Snake Sequence

Problem

You are given a grid of numbers. A snake sequence is made up of adjacent numbers such that for each number, the number on the right or the number below it is +1 or -1 its value. For example,

1 3 2 6 8
-9 7 1 -1 2
1 5 0 1 9

In this grid, (3, 2, 1, 0, 1) is a snake sequence. Given a grid, find the longest snake sequences and their lengths 

(so there can be multiple snake sequences with the maximum length).

Solution

public int findSnakeSequence(int[][] matrix) {
//        List<List<Integer>> res = ArrayList<ArrayList<Integer>>();
    if(matrix == null || matrix.length == 0) {
        return -1;
    }
    int m = matrix.length;
    int n = matrix[0].length;
    
    int[][] dp = new int[m][n];
    int globalMax = 0;
    
    //initialize
    dp[0][0] = 1;
    for(int i=1; i<n; i++) {
        if(Math.abs(matrix[0][i] - matrix[0][i-1]) == 1) 
            dp[0][i] = dp[0][i-1] + 1;
        else
            dp[0][i] = 1;
    }
    
    for(int i=1; i<m; i++) {
        if(Math.abs(matrix[i][0] - matrix[i-1][0]) == 1) 
            dp[i][0] = dp[i-1][0] + 1;
        else
            dp[i][0] = 1;
    }
    
    for(int i=1; i<m; i++) {
        for(int j=1; j<n; j++) {
            int max = 1;
            if(Math.abs(matrix[i][j] - matrix[i][j-1]) == 1)
                max = dp[i][j-1] + 1;
            if(Math.abs(matrix[i][j] - matrix[i-1][j]) == 1)
                max = Math.max(max, dp[i-1][j] + 1);
            dp[i][j] = max;
            globalMax = Math.max(max, globalMax);
        }
    }
    
    for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
        System.out.print(dp[i][j] + " ");
    }
    System.out.print("\n");
    }
    
    return globalMax;
        
}