Solution 1 for Scaler Topics Fortnightly Contest - 28
Lucky Number
This article is part of the Scaler Topics Fortnightly Contest - 28
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Let’s recall the conditions under which we can rearrange the letters of a word to form a palindrome. This is achievable if the number of letters with odd occurrences is not greater than 1.
In our problem, it suffices to verify that the number of letters with odd occurrences (denoted as x) is not greater than A+1. Let’s prove this assertion.
If x>A+1, then it is impossible to obtain the answer because, with A operations, we cannot reduce the number of letters with odd occurrences to not be greater than 1. On the other hand, we can simply remove the character with an odd number of occurrences in each removal iteration and decrease the number of odd occurrences. If there are no such characters, we can choose any character and remove it, thus ensuring there is only 1 character with an odd occurrence.
Time complexity : O(B.size()) Space complexity: O(1)
C++ Implementation
Java Implementation
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