Number of n digit stepping numbers | Java program to calculate the number of n digit stepping numbers . ; function that calculates the answer ; dp [ i ] [ j ] stores count of i digit stepping numbers ending with digit j . ; if n is 1 then answer will be 10. ; Initialize values for count of digits equal to 1. ; Compute values for count of digits more than 1. ; If ending digit is 0 ; If ending digit is 9 ; For other digits . ; stores the final answer ; driver program to test the above function
class GFG { static long answer ( int n ) { int dp [ ] [ ] = new int [ n + 1 ] [ 10 ] ; if ( n == 1 ) return 10 ; for ( int j = 0 ; j <= 9 ; j ++ ) dp [ 1 ] [ j ] = 1 ; for ( int i = 2 ; i <= n ; i ++ ) { for ( int j = 0 ; j <= 9 ; j ++ ) { if ( j == 0 ) dp [ i ] [ j ] = dp [ i - 1 ] [ j + 1 ] ; else if ( j == 9 ) dp [ i ] [ j ] = dp [ i - 1 ] [ j - 1 ] ; else dp [ i ] [ j ] = dp [ i - 1 ] [ j - 1 ] + dp [ i - 1 ] [ j + 1 ] ; } } long sum = 0 ; for ( int j = 1 ; j <= 9 ; j ++ ) sum += dp [ n ] [ j ] ; return sum ; } public static void main ( String args [ ] ) { int n = 2 ; System . out . println ( answer ( n ) ) ; } }