Python3程序：最小化字符更改次数，使字符串的左旋转和右旋转相同

# Function to find the minimum characters to be removed from the string
def getMinimumChange(str, n):
   # Initialize answer by N in variable minNum
   minChanges = n
   # If the length of the string is even
   if (n % 2 == 0):
      # Created frequency array for Even index
      freqEvenIdx = {}
      # Created frequency array for odd index
      freqOddIdx = {}
      # Traverse for loop to intialize both the frequency array freqEvenddIdx and freqOddIdx to 0
      for ch in range(ord('a'), ord('z') + 1):
         freqEvenIdx[chr(ch)] = 0
         freqOddIdx[chr(ch)] = 0
      # at odd and even index
      for i in range(n):
         if (i % 2 == 0):
            if str[i] in freqEvenIdx:
               freqEvenIdx[str[i]] += 1
         else:
            if str[i] in freqOddIdx:
               freqOddIdx[str[i]] += 1
      # Create variable evenIdxMax and OddIdxMax to store maximum frequency of even place character and odd place character respectively
      evenIdxMax = 0
      oddIdxMax = 0
      # Traverse for loop from a to z to update variable evenIdxMax and OddIdxMax
      for ch in range(ord('a'), ord('z') + 1):
         evenIdxMax = max(evenIdxMax, freqEvenIdx[chr(ch)])
         oddIdxMax = max(oddIdxMax, freqOddIdx[chr(ch)])
      # Update the answerin variable minChanges
      minChanges = minChanges - evenIdxMax - oddIdxMax
   # If the length of the string is odd
   else:
      # Create array to store frequecy of character of the string
      freq = {}
      #  initialize the the freq array
      for ch in range('a', 'z'):
         freq[chr(ch)] = 0
      # Stores the frequency of the characters of the string while traversing the string
      for i in range(n):
         if str[i] in freq:
            freq[str[i]] += 1
      # Stores the maximum freuency of character of the string in variable freqMax
      freqMax = 0
      #  Traverse the for loop to update freqMax
      for ch in range('a', 'z'):
         freqMax = max(freqMax, freq[chr(ch)])
      # Update the answer in variable minChanges
      minChanges = minChanges - freqMax
# Return final answer minChanges
   return minChanges
str = "wxyz"  # Given String
n = len(str)  # Getting size of the given string
# Call the function to get minimum number of changes to make left and right rotated string same
res = getMinimumChange(str, n)
# Print result
print(
   "The minimum number of changes to make the left and right rotated string same are: "
)
print(res)