剑指offer 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         for(int i = 0; i < length; i ++) {
11             int value = numbers[i];
12             if( value >= length)
13                 value -= length;
14             if( numbers[value] < length)
15                 numbers[value] += length;
16             else {
17                 *duplication = value;
18                 return true;
19             }
20         }
21         return false;
22     }
23 };