Package g0401_0500.s0451_sort_characters_by_frequency

Class Solution

java.lang.Object
g0401_0500.s0451_sort_characters_by_frequency.Solution
public class Solution extends java.lang.Object
451 - Sort Characters By Frequency.

Medium

Given a string s, sort it in decreasing order based on the frequency of the characters. The frequency of a character is the number of times it appears in the string.

Return the sorted string. If there are multiple answers, return any of them.

Example 1:

Input: s = “tree”

Output: “eert”

Explanation: ‘e’ appears twice while ‘r’ and ‘t’ both appear once. So ‘e’ must appear before both ‘r’ and ‘t’. Therefore “eetr” is also a valid answer.

Example 2:

Input: s = “cccaaa”

Output: “aaaccc”

Explanation: Both ‘c’ and ‘a’ appear three times, so both “cccaaa” and “aaaccc” are valid answers. Note that “cacaca” is incorrect, as the same characters must be together.

Example 3:

Input: s = “Aabb”

Output: “bbAa”

Explanation: “bbaA” is also a valid answer, but “Aabb” is incorrect. Note that ‘A’ and ‘a’ are treated as two different characters.

Constraints:

  • 1 <= s.length <= 5 * 105
  • s consists of uppercase and lowercase English letters and digits.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    java.lang.String
    frequencySort(java.lang.String s)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • frequencySort

      public java.lang.String frequencySort(java.lang.String s)