Given a string S of length N. The task is to find the minimum number of steps required on strings, so that it has exactly K different alphabets all with the same frequency.
Note: In one step, we can change a letter to any other letter.
Input: S = "abbc", N = 4, K = 2 Output: 1 In one step convert 'c' to 'a'. Hence string has two different letters a and b both occurring 2 times.
- Check if K divides N, then only it is possible to convert the given string, otherwise not.
- Maintain the count of all alphabets present in string S, in an array A.
- Evaluate E = N/K, the frequency with which alphabets will be present in the final string.
- Separate the alphabets with frequency more than or equal to E and less than E in two parts.
- Maintain the number of steps required for each alphabet to convert its count to E, sort these vector obtained in above step.
- Lastly, take all possibility to pick:
Set 1 : 0 Set 2 : K Set 1 : 1 Set 2 : K-1 .... so on
- Keep a ans variable to calculate minimum number of steps among all possibility in step 6.
- Say L1 is the number of operation required on Set 1, L2 is the number of operations required on set 2. Then total operations required is maximum of L1, L2 . As suppose ‘a’ is required one less in string while ‘b’ is required one more than we can change ‘a’ to ‘b’, thus reducing number of steps.
Below is the implementation of the above appraoch:
- Minimum increment by k operations to make all elements equal
- Minimum move to end operations to make all strings equal
- Minimum operations of given type to make all elements of a matrix equal
- Minimum operations required to make every element greater than or equal to K
- Minimum number of given operations required to make two strings equal
- Minimum number of operations to move all uppercase characters before all lower case characters
- Character whose frequency is equal to the sum of frequencies of other characters of the given string
- Find the number of operations required to make all array elements Equal
- Minimum operations to make sum of neighbouring elements <= X
- Minimum operations to make GCD of array a multiple of k
- Minimum no. of operations required to make all Array Elements Zero
- Find minimum operations needed to make an Array beautiful
- Minimum characters to be added at front to make string palindrome
- Minimum replacements to make adjacent characters unequal in a ternary string
- Minimum number of characters to be removed to make a binary string alternate
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