99 解(1) 二叉排序树 查找成功得平均长度: (2) 排序后:Apr,Aug,Dec,Feb,Jan,July,June,Mar,May,Nov,Oct,Sep 1 2 3 4 5 6 7 8 9 10 11 12 二叉排序树: July July MarJanFebAugSepOctNovJuneyMayAprDec Mar Jan Feb Aug Sep Oct Nov Juney May