快速排序

(void)kuaisupaixu:(NSMutableArray *)arr low:(NSInteger)left High:(NSInteger)right {
if(left < right) {
NSInteger i = left;
NSInteger j = right;
NSInteger key = [arr[left] integerValue];

  while (i < j) {
      while (i < j && key <= [arr[j] integerValue]) {
          j--;
      }
      arr[i] = arr[j];
      while (i < j && key >= [arr[i] integerValue]) {
          i++;
      }
      arr[j] = arr[i];
  }
  arr[i] = [NSNumber numberWithInteger:key];
  [self kuaisupaixu:arr low:left High:i - 1];
  [self kuaisupaixu:arr low:i + 1 High:right];

}
NSLog(@"%@",arr);
}