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Minimum changes required to make each path in a matrix palindrome | Function for counting changes.
Maximum distance possible is ( n - 1 + m - 1 ).
Stores the maximum element.
Update the maximum.
Stores frequencies of values for respective distances.
Initialize frequencies of cells as 0.
Count frequencies of cell values in the matrix.
Increment frequency of value at distance i + j.
Store the most frequent value at i - th distance from ( 0 , 0 ) and ( N - 1 , M - 1 ).
Calculate max frequency and total cells at distance i.
Count changes required to convert all cells at i - th distance to most frequent value.
Driver code"
How can the above be solved in Python?
assistant
#Here is code to minimum changes required to make each path in a matrix palindrome and the other steps required.
 def countChanges ( matrix , n , m ) :
	dist = n + m - 1
	Max_element = 0
	for i in range ( n ) :
		for j in range ( m ) :
			Max_element = max ( Max_element , matrix [ i ] [ j ] )
	freq = [ [ 0 for i in range ( Max_element + 1 ) ] for j in range ( dist ) ]
	for i in range ( dist ) :
		for j in range ( Max_element + 1 ) :
			freq [ i ] [ j ] = 0
	for i in range ( n ) :
		for j in range ( m ) :
			freq [ i + j ] [ matrix [ i ] [ j ] ] += 1
	min_changes_sum = 0
	for i in range ( dist // 2 ) :
		maximum = 0
		total_values = 0
		for j in range ( Max_element + 1 ) :
			maximum = max ( maximum , freq [ i ] [ j ] + freq [ n + m - 2 - i ] [ j ] )
			total_values += ( freq [ i ] [ j ] + freq [ n + m - 2 - i ] [ j ] )
		min_changes_sum += total_values - maximum
	return min_changes_sum
if __name__ == ' _ _ main _ _ ' :
	mat = [ [ 7 , 0 , 3 , 1 , 8 , 1 , 3 ] , [ 0 , 4 , 0 , 1 , 0 , 4 , 0 ] , [ 3 , 1 , 8 , 3 , 1 , 0 , 7 ] ]
	minChanges = countChanges ( mat , 3 , 7 )
	print ( minChanges )