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         bool res=false;
11         if(length==0) return res;
12         vector<int> num(length,0);
13         for(int i=0;i<length;i++)
14             {
15             if(numbers[i]>=0&&numbers[i]<=length-1)
16                 {
17                 num[numbers[i]]++;
18                 if(num[numbers[i]]>1)
19                 {
20                     *duplication=numbers[i];
21                     res=true;
22                 } 
23             }
24             else return false;
25         }
26         return res;
27     }
28 };