如何在NetLogo中所有斑块被着色时让海龟停止运行？

需要实现的功能：当海龟把所有红色斑块都改成蓝色后，停在最后一个被着色的斑块处，同时记录运行所用的tick数。

现有代码 #

turtles-own [time-since-last-found]

to setup
  ca
  ask n-of num-clusters patches [
      ask n-of 20 patches in-radius 5 [
          set pcolor red
      ]
  ]
  crt 1 [ set shape "person"
          set color yellow
          set size 2
          set time-since-last-found 999
          pen-down
  ]
  reset-ticks
end

to go
  ask turtles [search]
  tick
end

to search
   ifelse time-since-last-found < 20 [
          right (random 181) - 90
   ] [
          right (random 21) - 10
   ]
   fd 1
   ifelse pcolor = red [
          set time-since-last-found 0 set pcolor blue
   ] [
          set time-since-last-found time-since-last-found + 1
   ]
end

修改方案 #

核心思路是跟踪剩余未着色的红色斑块数量，当数量归0时停止海龟行动。具体修改步骤如下：

1. 添加全局变量跟踪剩余红色斑块
   在代码最顶部添加全局变量，用来记录还未被改成蓝色的红色斑块数：

globals [ remaining-red-patches ]

2. 初始化剩余斑块数
   修改setup过程，在最后加入计算初始红色斑块数量的代码：

to setup
  ca
  ask n-of num-clusters patches [
      ask n-of 20 patches in-radius 5 [
          set pcolor red
      ]
  ]
  crt 1 [ set shape "person"
          set color yellow
          set size 2
          set time-since-last-found 999
          pen-down
  ]
  ; 初始化剩余红色斑块数量
  set remaining-red-patches count patches with [pcolor = red]
  reset-ticks
end

3. 更新剩余斑块数并添加停止判断
   修改search过程，每次把红色斑块改成蓝色时同步减少剩余斑块数，且提前判断是否已完成所有着色：

to search
   ; 如果所有斑块都已着色，直接停止行动
   if remaining-red-patches = 0 [ stop ]
   
   ifelse time-since-last-found < 20 [
          right (random 181) - 90
   ] [
          right (random 21) - 10
   ]
   fd 1
   ifelse pcolor = red [
          set time-since-last-found 0 
          set pcolor blue
          ; 剩余红色斑块数减1
          set remaining-red-patches remaining-red-patches - 1
   ] [
          set time-since-last-found time-since-last-found + 1
   ]
end

4. 控制go循环停止
   修改go过程，当剩余红色斑块为0时，不再执行海龟行动和tick计数：

to go
  if remaining-red-patches > 0 [
    ask turtles [search]
    tick
  ]
end

修改完成后，当最后一个红色斑块被改成蓝色时，remaining-red-patches会变为0，海龟在下一次执行search时会直接停止，go循环也会终止，此时界面显示的ticks数值就是整个过程所用的时间。

内容的提问来源于stack exchange，提问作者echakee