#Leetcode# 451. Sort Characters By Frequency
作者:互联网
https://leetcode.com/problems/sort-characters-by-frequency/
Given a string, sort it in decreasing order based on the frequency of characters.
Example 1:
Input: "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: "cccaaa" Output: "cccaaa" Explanation: Both 'c' and 'a' appear three times, so "aaaccc" is also a valid answer. Note that "cacaca" is incorrect, as the same characters must be together.
Example 3:
Input: "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.
代码:
class Solution { public: string frequencySort(string s) { string ans = ""; int len = s.length(); unordered_map<char, int> mp; priority_queue<pair<int, char> > q; for(int i = 0; i < len; i ++) mp[s[i]] ++; for(auto i : mp) q.push({i.second, i.first}); while(!q.empty()) { int k = q.top().first; char c = q.top().second; for(int i = 0; i < k; i ++) ans += c; q.pop(); } return ans; } };
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FH 明天就肥家放假啦
标签:Sort,string,int,451,Frequency,characters,ans,Input,appear 来源: https://www.cnblogs.com/zlrrrr/p/10339708.html