一个活动,n个女生手里拿着长短不一的玫瑰花,无序的排成一排,一个男生从头走到尾,试图拿更长的玫瑰花,一旦拿了一朵就不能再拿其他的,错过了就不能回头,问最好的策略?

“`” 参考回答：

选择的策略为不选取前r-1个女生,只从剩下的n-r+1个女生开始选取,若任何一个女生比之前的女生玫瑰花都长则选取这个女生,假设从第r个女生开始选,则第k个被选中的女生拥有最长玫瑰花的概率为:<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619406589_630610B7C540D8F2CA55AA2EDC4531AB""><img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619417804_69E9A7DAE41DD6A06F7F6282557E75E3""><img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619430851_6465CCE749534A222C43795C8ABA1AEB"">

<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619444612_9FF6608A83E4E9B0031D01BD20466D7A"">

当第r个为玫瑰最长的女生,那么她被选中概率比第r+1个女生大,则<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619496892_5E1176B211EFF517C07C096D502EF44D"">即<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619521411_54B5AD21541A8870F3ADEF5AEBE2BFFE"">因

<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619537383_FE1B998A8EE01EDD8FB1716886A503EC"">所以<img alt=""img"" referrerpolicy=""no-referrer"" src=""https://uploadfiles.nowcoder.com/images/20190315/311436_1552619594725_6CAC77CA69DADD49D4DEB6935C53C414"">在此策略下,玫瑰最长女生被选中概率为0.368

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