Function to pre - calculate value of all combinations nCr
def combi ( n , k ) : NEW_LINE INDENT for i in range ( n + 1 ) : NEW_LINE INDENT for j in range ( min ( i , k ) + 1 ) : NEW_LINE INDENT if ( j == 0 or j == i ) : NEW_LINE INDENT C [ i ] [ j ] = 1 NEW_LINE DEDENT else : NEW_LINE INDENT C [ i ] [ j ] = ( C [ i - 1 ] [ j - 1 ] % MOD + C [ i - 1 ] [ j ] % MOD ) % MOD NEW_LINE DEDENT DEDENT DEDENT DEDENT