public static boolean isSequence(int[][] a){
        int n = a.length;
        /* 1) Get the minimum element in array */
        int min = getMinValue(a);

        /* 2) Get the maximum element in array */
        int max = getMaxValue(a);

            if (n < 1)
                return false;



            /* 3) max - min + 1 is equal to n,  then only check all elements */
            if (max - min + 1 == n)
            {
            /* Create a temp array to hold visited flag of all elements.
               Note that, calloc is used here so that all values are initialized
               as false */
                boolean visited[] = new boolean[n];
                int i;
                for (i = 0; i < n; i++)
                {
                    for (int j = 0; j < a[i].length; j++) {
                        if (visited[a[i][j] - min] != false)
                            return false;


                        visited[a[i][j] - min] = true;
                    }
                }
                    /* If we see an element again, then return false */


                    /* If visited first time, then mark the element as visited */



                /* If all elements occur once, then return true */
                return true;
            }
            return false; // if (max - min  + 1 != n)
        }