Maximize palindromic strings after character swaps
Problem Description
You are provided with an array of n lowercase strings, arr.
You can perform an operation any number of times:
- Choose two distinct strings,
arr[i]andarr[j], from the array. - Pick one character from
arr[i]and one character fromarr[j]. - Swap these two chosen characters.
After performing any sequence of such swaps, your goal is to determine the maximum possible number of strings in arr that can be made into palindromes.
Constraints and Notes
- Swaps can be performed between any pair of strings, and operations can be repeated indefinitely.
- The length of each string must remain unchanged throughout the operations.
Example
Input: arr = ["pass", "sas", "asps", "df"]
Output: 3
(It is possible to make 3 of the strings palindromes.)
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Core dilemma
The central engineering conflict is optimally distributing a globally fixed pool of characters (where only character counts matter) among multiple strings to satisfy local palindrome conditions, while maximizing the number of strings that become palindromes. This is a resource allocation problem under a global invariant.
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Maximize palindromic strings after character swaps
Problem Description
You are provided with an array of n lowercase strings, arr.
You can perform an operation any number of times:
- Choose two distinct strings,
arr[i]andarr[j], from the array. - Pick one character from
arr[i]and one character fromarr[j]. - Swap these two chosen characters.
After performing any sequence of such swaps, your goal is to determine the maximum possible number of strings in arr that can be made into palindromes.
Constraints and Notes
- Swaps can be performed between any pair of strings, and operations can be repeated indefinitely.
- The length of each string must remain unchanged throughout the operations.
Example
Input: arr = ["pass", "sas", "asps", "df"]
Output: 3
(It is possible to make 3 of the strings palindromes.)