[2021 Spring] CS61A Project 3: Ants Vs. SomeBees (Phase 3)

项目说明：https://inst.eecs.berkeley.edu/~cs61a/sp21/proj/ants/
蚂蚁大战蜜蜂 灵感来源：植物大战僵尸（Plants Vs. Zombies，PVZ）
Phase 1： https://www.cnblogs.com/ikventure/p/14986805.html
Phase 2： https://www.cnblogs.com/ikventure/p/14988467.html
Phase 3： https://www.cnblogs.com/ikventure/p/14992754.html
Phase 4： https://www.cnblogs.com/ikventure/p/14994734.html
效果展示： https://www.cnblogs.com/ikventure/p/15001093.html

目录

• Phase 3: More Ants!
  • Problem 6 (2 pt)
  • Problem 7 (3 pt)
  • Problem 8 (3 pt)
  • Problem 9 (1 pt)

Phase 3: More Ants!

继续添加蚂蚁类型

Problem 6 (2 pt)

WallAnt类似PVZ坚果墙，高生命不攻击。

Class	Food Cost	Initial Health
WallAnt	4	4

action：坚果墙自身不行动，action方法从Insect类继承即可。
名称：wall.name = 'Wall'
health：初始化时传入，默认4
只要是需要实例化的Ant类，都要把implemented设为True。
补充一下注释比较好看。
代码：

# BEGIN Problem 6
# The WallAnt class
class WallAnt(Ant):
    """WallAnt does nothing each turn but it has a large health value."""

    name = 'Wall'
    food_cost = 4
    implemented = True

    def __init__(self, health=4):
        super().__init__(health)
# END Problem 6

Problem 7 (3 pt)

HungryAnt类似PVZ大嘴花，可以吞掉自身位置的随机一只蜜蜂，但是吞掉蜜蜂后需要等待3回合的咀嚼CD，没有蜜蜂时不行动。

Class	Food Cost	Initial Health
HungryAnt	4	1

思路：
chewing是实例属性，每个实例独立CD，初始化为0
名称：'Hungry'
chew_duration为类属性

action：
当self.chewing为0且当前位置有蜜蜂则随机选择一个，health置0，注意置0后要从当前位置清出。
其他情况CD不为0则减1。

代码：

# BEGIN Problem 7
# The HungryAnt Class
class HungryAnt(Ant):
    """A HungryAnt will select a random Bee from its place and eat it whole"""

    name = 'Hungry'
    food_cost = 4
    implemented = True
    chew_duration = 3

    def __init__(self, health=1):
        super().__init__(health)
        self.chewing = 0

    def action(self, gameState):
        if self.chewing == 0 and self.place.bees[:]:
            selected_bee = bee_selector(self.place.bees)
            selected_bee.health = 0
            selected_bee.reduce_health(0)
            self.chewing = self.chew_duration
        else:
            if self.chewing != 0:
                self.chewing -= 1
# END Problem 7

Problem 8 (3 pt)

BodyguardAnt类似PVZ南瓜头，是一种容器类蚂蚁ContainerAnt，套在其他蚂蚁上保护蚂蚁（同一位置）。被蜜蜂攻击时，南瓜头掉血，内部蚂蚁照常行动不掉血。南瓜头被消灭，内部蚂蚁依然留在该位置上（不再被保护）。

Class	Food Cost	Initial Health
BodyguardAnt	4	2

南瓜头中的蚂蚁存放在南瓜头的contained_ant实例属性中，而The container Ant南瓜头存放在place的蚂蚁实例属性中。

ContainerAnt类：

• contain_ant方法：传入ant设置为南瓜头的contained_ant。
• action方法：内部存在蚂蚁时，调用该蚂蚁的action方法。
• can_contain方法：传入另一只蚂蚁other，在南瓜头内没有蚂蚁（contained_ant为None），且蚂蚁other不是南瓜头（容器类蚂蚁）时，返回True。

    def can_contain(self, other):
        # BEGIN Problem 8
        "*** YOUR CODE HERE ***"
        if self.contained_ant is None and not other.is_container():
            return True
        return False
        # END Problem 8

    def contain_ant(self, ant):
        # BEGIN Problem 8
        "*** YOUR CODE HERE ***"
        self.contained_ant = ant
        # END Problem 8

    def action(self, gamestate):
        # BEGIN Problem 8
        "*** YOUR CODE HERE ***"
        if self.contained_ant:
            self.contained_ant.action(gamestate)
        # END Problem 8

Ant类的add_to方法，允许一个container和一个非container蚂蚁占据同一个位置，规则如下：

1. 原蚂蚁可以contain被加入的蚂蚁，原蚂蚁调用contain_ant。
2. 被加入的蚂蚁可以contain原蚂蚁，被加入的蚂蚁调用contain_ant，注意修改place.ant。
3. 前两条均不满足，触发AssertionError。

    def add_to(self, place):
        if place.ant is None:
            place.ant = self
        else:
            # BEGIN Problem 8
            if place.ant.can_contain(self) and place.ant.contained_ant is None:
                place.ant.contain_ant(self)
            elif self.is_container() and self.can_contain(place.ant):
                self.contain_ant(place.ant)
                place.ant = self
            else:
                assert place.ant is None, 'Two ants in {0}'.format(place)
            # END Problem 8
        Insect.add_to(self, place)

BodyguardAnt类：
BodyguardAnt.__init__设置ant的初始生命值。

class BodyguardAnt(ContainerAnt):
    """BodyguardAnt provides protection to other Ants."""

    name = 'Bodyguard'
    food_cost = 4
    # OVERRIDE CLASS ATTRIBUTES HERE
    # BEGIN Problem 8
    implemented = True   # Change to True to view in the GUI

    def __init__(self, health=2):
        super().__init__(health)
    # END Problem 8

Problem 9 (1 pt)

TankAnt相当于加强版南瓜头，可以对当前位置的所有蜜蜂造成1点伤害。

Class	Food Cost	Initial Health
TankAnt	6	2

action在BodyguardAnt的基础上，调用Bee.reduce_health即可。
代码：

# BEGIN Problem 9
# The TankAnt class
class TankAnt(ContainerAnt):
    """TankAnt provides protection to other Ants and make damage to Bees."""

    name = 'Tank'
    food_cost = 6
    damage = 1
    implemented = True

    def __init__(self, health=2):
        super().__init__(health)
    
    def action(self, gamestate):
        if self.contained_ant:
            self.contained_ant.action(gamestate)
        for bee in self.place.bees[:]:
            bee.reduce_health(self.damage)
# END Problem 9