1.1确定字符各异

 1 class Different
 2 {
 3 
 4     bool quick_check(string &str, int low, int high)
 5     {
 6         int first = low, last = high;
 7         char key = str[first];
 8 
 9         if(low >= high)
10         {
11             return true;
12         }
13 
14         while(first < last)
15         {
16             while(first < last && str[last] >= key)
17             {
18                 last--;
19             }
20 
21             str[first] = str[last];
22             while(first < last && str[first] <= key)
23             {
24                 first++;
25             }
26             str[last] = str[first];
27         }
28 
29         str[first] = key;
30         if(first > low && str[first] == str[first - 1])
31         {
32             return false;
33         }
34 
35         if(first < high && str[first] == str[first + 1])
36         {
37             return false;
38         }
39         return quick_check(str, low, first - 1) && quick_check(str, first + 1, high);
40     }
41 
42 public:
43     bool checkDifferent(string iniString)
44     {
45         // write code here
46         return quick_check(iniString, 0, iniString.size() - 1);
47 
48     }
49 };