Counts paths from a point to reach Origin | DP based function to count number of paths ; Fill entries in bottommost row and leftmost columns ; Fill DP in bottom up manner ; Driver Code
function countPaths ( n , m ) { var dp = Array ( n + 1 ) . fill ( 0 ) . map ( x => Array ( m + 1 ) . fill ( 0 ) ) ; for ( i = 0 ; i <= n ; i ++ ) dp [ i ] [ 0 ] = 1 ; for ( i = 0 ; i <= m ; i ++ ) dp [ 0 ] [ i ] = 1 ; for ( i = 1 ; i <= n ; i ++ ) for ( j = 1 ; j <= m ; j ++ ) dp [ i ] [ j ] = dp [ i - 1 ] [ j ] + dp [ i ] [ j - 1 ] ; return dp [ n ] [ m ] ; } var n = 3 , m = 2 ; document . write ( " " + countPaths ( n , m ) ) ;