131 lines
3.5 KiB
Kotlin
131 lines
3.5 KiB
Kotlin
/*Taken from http://try.kotlinlang.org/#/Examples/Longer%20examples/Life/Life.kt*/
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/**
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* This is a straightforward implementation of The Game of Life
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* See http://en.wikipedia.org/wiki/Conway's_Game_of_Life
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*/
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package life
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/*
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* A field where cells live. Effectively immutable
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*/
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class Field(
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val width: Int,
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val height: Int,
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// This function tells the constructor which cells are alive
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// if init(i, j) is true, the cell (i, j) is alive
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init: (Int, Int) -> Boolean
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) {
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private val live: Array<Array<Boolean>> = Array(height) { i -> Array(width) { j -> init(i, j) } }
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private fun liveCount(i: Int, j: Int)
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= if (i in 0..height - 1 &&
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j in 0..width - 1 &&
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live[i][j]) 1 else 0
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// How many neighbors of (i, j) are alive?
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fun liveNeighbors(i: Int, j: Int) =
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liveCount(i - 1, j - 1) +
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liveCount(i - 1, j) +
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liveCount(i - 1, j + 1) +
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liveCount(i, j - 1) +
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liveCount(i, j + 1) +
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liveCount(i + 1, j - 1) +
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liveCount(i + 1, j) +
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liveCount(i + 1, j + 1)
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// You can say field[i, j], and this function gets called
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operator fun get(i: Int, j: Int) = live[i][j]
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}
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/**
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* This function takes the present state of the field
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* and returns a new field representing the next moment of time
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*/
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fun next(field: Field): Field {
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return Field(field.width, field.height) { i, j ->
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val n = field.liveNeighbors(i, j)
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if (field[i, j])
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// (i, j) is alive
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n in 2..3 // It remains alive iff it has 2 or 3 neighbors
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else
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// (i, j) is dead
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n == 3 // A new cell is born if there are 3 neighbors alive
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}
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}
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/** A few colony examples here */
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fun main(args: Array<String>) {
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// Simplistic demo
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runGameOfLife("***", 3)
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// "Star burst"
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runGameOfLife("""
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_______
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___*___
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__***__
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___*___
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_______
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""", 10)
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// Stable colony
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runGameOfLife("""
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_____
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__*__
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_*_*_
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__*__
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_____
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""", 3)
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// Stable from the step 2
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runGameOfLife("""
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__**__
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__**__
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__**__
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""", 3)
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// Oscillating colony
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runGameOfLife("""
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__**____
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__**____
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____**__
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____**__
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""", 6)
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// A fancier oscillating colony
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runGameOfLife("""
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-------------------
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-------***---***---
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-------------------
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-----*----*-*----*-
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-----*----*-*----*-
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-----*----*-*----*-
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-------***---***---
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-------------------
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-------***---***---
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-----*----*-*----*-
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-----*----*-*----*-
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-----*----*-*----*-
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-------------------
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-------***---***---
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-------------------
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""", 10)
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}
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// UTILITIES
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fun runGameOfLife(fieldText: String, steps: Int) {
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var field = makeField(fieldText)
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for (step in 1..steps) {
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println("Step: $step")
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for (i in 0..field.height - 1) {
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for (j in 0..field.width - 1) {
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print(if (field[i, j]) "*" else " ")
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}
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println("")
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}
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field = next(field)
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}
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}
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fun makeField(s: String): Field {
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val lines = s.replace(" ", "").split('\n').filter({ it.isNotEmpty() })
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val longestLine = lines.toList().maxBy { it.length } ?: ""
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return Field(longestLine.length, lines.size) { i, j -> lines[i][j] == '*' }
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}
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