Leetcode 451. Sort Characters By Frequency

Reorder the characters of a string so that characters appear in descending order of their frequency, returning any valid ordering where identical characters are grouped together. Characters are case-sensitive (letters and digits allowed) and the string length can be up to 5e5.

Asked at:

Amazon

Microsoft

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Level

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Early October, 2025

Microsoft

Mid-level

Didn't want the Map and PriorityQueue Approach. INPUT: tree O/P: e : 2 t : 1 r : 1

Mid November, 2024

Amazon

Junior

Sort String by Frequency: Sort characters in a string in decreasing order of their frequency. If multiple answers exist, return any valid one.

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Leetcode 451. Sort Characters By Frequency

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