快速排序

private static void quickSort(int left, int right, int[] array) {
		if (left > right) {
			return;
		}

		int leftIndex = left, rightIndex = right, flag = array[left];
		while (leftIndex != rightIndex) {
			// 从右开始找比指定的基准数小的数
			while (leftIndex < rightIndex && array[rightIndex] >= flag) {
				rightIndex--;
			}
			// 从左开始找比指定的基准数大的数
			while (leftIndex < rightIndex && array[leftIndex] <= flag) {
				leftIndex++;
			}
			// 交换
			if (leftIndex < rightIndex) {
				int tmp = array[leftIndex];
				array[leftIndex] = array[rightIndex];
				array[rightIndex] = tmp;
			}
		}
		// 重置被用来比较的flag数
		array[left] = array[leftIndex];
		array[leftIndex] = flag;
		// 递归分治
		quickSort(left, leftIndex - 1, array);
		quickSort(rightIndex + 1, right, array);
	}