针对数组中有大量重复数优化

example

// 1,3,4,7,7,7,17,11,1,7

1 void QuickSort(int* arr, int from, int to); 2 void QSort(int* arr, int size); 3  4 void QuickSort(int* arr, int from, int to) 5 { 6     if(from >= to)    return; 7     int pivot = arr[to]; 8     // save the numbers of who's value equals pivot 9     int numsOfPivot = 0;10     int border = from;11 //                b     i12 //    1,3,4,7,7,7,17,11,1,713     for(int i = from; i <= to; i++)14     {15         if(arr[i] < pivot)16         {17             int temp = arr[i];18             arr[i] = arr[border];19             arr[border - numsOfPivot] = temp;20             ++border;21         }22         else if(arr[i] == pivot)23         {24             ++numsOfPivot;25             arr[i] = arr[border];26             ++border;27         }28     }29     // refill the duplicate of pivot at the behind of border30     while(numsOfPivot != 0)31     {32         arr[border-numsOfPivot] = pivot;33         --numsOfPivot;34     }35     QuickSort(arr,from,border-2-numsOfPivot);36     QuickSort(arr,border,to);37 }38 39 void QSort(int* arr, int size)40 {41     QuickSort(arr, 0, size-1);42 }