CF 1792A - GamingForces

Monocarp is playing a computer game. He's going to kill n monsters, the i-th of them has hi health.

Monocarp's character has two spells, either of which he can cast an arbitrary number of times (possibly, zero) and in an arbitrary order:

choose exactly two alive monsters and decrease their health by 1;

choose a single monster and kill it.

When a monster's health becomes 0, it dies.

What's the minimum number of spell casts Monocarp should perform in order to kill all monsters?

Monocarp 正在玩电脑游戏。 他要杀死 n 个怪物，其中第 i 个的生命值很高。

Monocarp 的角色有两个法术，他可以以任意顺序施展任意次数（可能为零）：

选择恰好两个活着的怪物并将其生命值降低 1；

选择一个怪物并杀死它。

当怪物的生命值变为0时，它就会死亡。

为了杀死所有怪物，Monocarp 最少需要施展多少次法术？

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对于生命值大于1的怪物，肯定是一招消灭掉最省时间了，只有是生命值为1的怪物才有一次选2个怪物，然后生命值－1的必要，于是就是求数组中1的怪物的数量即可；

当然还要判断一下奇数还是偶数；

下面是代码：