human
What is a code to number of pairs from the first N natural numbers whose sum is divisible by K and the other steps required given the following:
Number of pairs from the first N natural numbers whose sum is divisible by K | Function to find the number of pairs from the set of natural numbers up to N whose sum is divisible by K.
Declaring a Hash to store count.
Storing the count of integers with a specific remainder in Hash array.
Check if K is even.
Count of pairs when both integers are divisible by K.
Count of pairs when one remainder is R and other remainder is K - R.
Count of pairs when both the remainders are K / 2.
Count of pairs when both integers are divisible by K.
Count of pairs when one remainder is R and other remainder is K - R.
Driver code.
Print the count of pairs"
Solution in Python:
assistant
#Here is code to number of pairs from the first N natural numbers whose sum is divisible by K and the other steps required.
 def findPairCount ( N , K ) :
	count = 0 ;
	rem = [ 0 ] * K ;
	rem [ 0 ] = N // K ;
	for i in range ( 1 , K ) :
		rem [ i ] = ( N - i ) // K + 1 ;
	if ( K % 2 == 0 ) :
		count += ( rem [ 0 ] * ( rem [ 0 ] - 1 ) ) // 2 ;
		for i in range ( 1 , K // 2 ) :
			count += rem [ i ] * rem [ K - i ] ;
		count += ( rem [ K // 2 ] * ( rem [ K // 2 ] - 1 ) ) // 2 ;
	else :
		count += ( rem [ 0 ] * ( rem [ 0 ] - 1 ) ) // 2 ;
		for i in rage ( 1 , K // 2 + 1 ) :
			count += rem [ i ] * rem [ K - i ] ;
	return count ;
if __name__ == " _ _ main _ _ " :
	N = 10 ; K = 4 ;
	print ( findPairCount ( N , K ) ) ;