human
What is a code to sum of elements in range L and the other steps required given the following:
Sum of elements in range L | Function to calculate the sum if n is even.
Both l and r are to the left of mid.
First and last element.
Total number of terms in the sequence is r - l + 1.
Use of formula derived.
Both l and r are to the right of mid.
First and last element.
Use of formula derived.
Left is to the left of mid and right is to the right of mid.
Take two sums i . e left and right differently and add.
First and last element.
total terms.
no of terms.
The first even number is 2.
The last element is.
formula applied.
Function to calculate the sum if n is odd.
Take ceil value if n is odd.
Both l and r are to the left of mid.
First and last element.
number of terms.
formula.
both l and r are to the right of mid.
first and last term ,.
no of terms.
formula used.
If l is on left and r on right.
calculate separate sums.
first half.
calculate terms.
second half.
add both halves.
Function to find the sum between L and R.
If n is even.
If n is odd.
Driver Code"
How can the above be solved in Python?
assistant
#Here is code to sum of elements in range L and the other steps required.
 def sumeven ( n , l , r ) :
	sum = 0
	mid = n // 2
	if ( r <= mid ) :
		first = ( 2 * l - 1 )
		last = ( 2 * r - 1 )
		no_of_terms = r - l + 1
		sum = ( ( no_of_terms ) * ( ( first + last ) ) ) // 2
	elif ( l >= mid ) :
		first = ( 2 * ( l - n // 2 ) )
		last = ( 2 * ( r - n // 2 ) )
		no_of_terms = r - l + 1
		sum = ( ( no_of_terms ) * ( ( first + last ) ) ) // 2
	else :
		sumleft , sumright = 0 , 0
		first_term1 = ( 2 * l - 1 )
		last_term1 = ( 2 * ( n // 2 ) - 1 )
		no_of_terms1 = n // 2 - l + 1
		sumleft = ( ( ( no_of_terms1 ) * ( ( first_term1 + last_term1 ) ) ) // 2 )
		first_term2 = 2
		last_term2 = ( 2 * ( r - n // 2 ) )
		no_of_terms2 = r - mid
		sumright = ( ( ( no_of_terms2 ) * ( ( first_term2 + last_term2 ) ) ) // 2 )
		sum = ( sumleft + sumright ) ;
	return sum
def sumodd ( n , l , r ) :
	mid = n // 2 + 1 ;
	sum = 0
	if ( r <= mid ) :
		first = ( 2 * l - 1 )
		last = ( 2 * r - 1 )
		no_of_terms = r - l + 1
		sum = ( ( ( no_of_terms ) * ( ( first + last ) ) ) // 2 )
	elif ( l > mid ) :
		first = ( 2 * ( l - mid ) )
		last = ( 2 * ( r - mid ) )
		no_of_terms = r - l + 1
		sum = ( ( ( no_of_terms ) * ( ( first + last ) ) ) // 2 )
	else :
		sumleft , sumright = 0 , 0
		first_term1 = ( 2 * l - 1 )
		last_term1 = ( 2 * mid - 1 )
		no_of_terms1 = mid - l + 1
		sumleft = ( ( ( no_of_terms1 ) * ( ( first_term1 + last_term1 ) ) ) // 2 )
		first_term2 = 2
		last_term2 = ( 2 * ( r - mid ) )
		no_of_terms2 = r - mid
		sumright = ( ( ( no_of_terms2 ) * ( ( first_term2 + last_term2 ) ) ) // 2 )
		sum = ( sumleft + sumright )
	return sum
def rangesum ( n , l , r ) :
	sum = 0
	if ( n % 2 == 0 ) :
		return sumeven ( n , l , r ) ;
	else :
		return sumodd ( n , l , r )
if __name__ == " _ _ main _ _ " :
	n = 12
	l = 1
	r = 11 ;
	print ( rangesum ( n , l , r ) )