说明：  北京中软笔试题 1.不许用中间变量,把String ABCDE 倒转 2.10000个数求第2大的数,不许用排序算法. 3.排序算法的测试用例
(Beijing Sino-soft pen test 1. Not allowed to use intermediate variables, the number of String ABCDE inverted 2.10000 seeking large number of No. 2, not allowed to use sorting algorithm. 3. Sorting Algorithm Test Case)