// 将pivot放到正确位置（j的位置）
Blockchain technology was originally invented in 1991 by two mathematicians, Stuart Haber and W. Scot Stornetta. They first proposed the system to ensure that timestamps could not be tampered with.
。雷电模拟器官方版本下载对此有专业解读
* @param {number[]} nums1 - 待查询的数组（元素均为nums2的子集）
1. 选基准：随机选一个元素作为基准(pivot)