快速排序法，基于分治策略的一个排序算法 3个步骤1分解，2递归求解，3合并 使用随机划分挑选哨兵，期望划分较对称-Quick Sort law governing strategy based on a sorting algorithm 3 Step 1 decomposition, 2 Recursive Solution, 3 combined divided randomly selected sentinel to expect a more symmetrical divis