【字符串】767. 重构字符串

 1 class Solution {
 2 public:
 3     struct elm
 4     {
 5         char alp;
 6         int cnt;
 7         friend bool operator <(elm a,elm b)
 8         {
 9             return a.cnt<b.cnt;
10         }
11     };
12 
13 public:
14     string reorganizeString(string S) 
15     {
16         priority_queue<elm> q;
17 
18         unordered_map<char,int> mp;
19 
20         for(auto s:S)
21         {
22             mp[s]++;
23         }
24 
25         for(auto p:mp)
26         {
27             elm t;
28             t.alp=p.first;
29             t.cnt=p.second;
30             q.push(t);
31         }
32 
33         int i=q.top().cnt;
34         if(S.size() % 2 && i > S.size() / 2 + 1)
35         {
36             return "";
37         }
38 
39         if(S.size() % 2 == 0 && i > S.size() / 2)
40         {
41             return "";
42         }
43         i=0;
44         while(!q.empty())
45         {
46             char t=q.top().alp;
47             int k=q.top().cnt;
48             while(k--)
49             {
50                 if(i>=S.size())
51                 {
52                     i=1;
53                 }
54                 S[i]=t;
55                 i+=2;
56             }
57             q.pop();
58         }
59         return S;
60     }
61 };