数组中重复的数字

 1 class Solution {
 2 public:
 3     // Parameters:
 4     //        numbers:     an array of integers
 5     //        length:      the length of array numbers
 6     //        duplication: (Output) the duplicated number in the array number
 7     // Return value:       true if the input is valid, and there are some duplications in the array number
 8     //                     otherwise false
 9     bool duplicate(int numbers[], int length, int* duplication) {
10         if(length < 2)
11             return 0;
12         map<int,int> mm;
13         for (int i = 0; i< length ; ++i)
14         {
15             if (mm.count(numbers[i])==0)
16             {
17                 mm[numbers[i]] = 1;
18             }
19             else
20             {
21                 ++mm[numbers[i]];
22             }
23         }
24 
25         for(map<int,int>::iterator it = mm.begin() ;it != mm.end() ; ++it)
26         {
27             if (it->second > 1)
28             {
29                 * duplication = it->first;
30                 return 1;
31             }
32         }
33         return 0;
34     }
35 };