Zalim Bashorov
142 lines
3.3 KiB
Kotlin
Vendored
142 lines
3.3 KiB
Kotlin
Vendored
/**
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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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/*
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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
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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 return 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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printField("***", 3)
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// "Star burst"
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printField("""
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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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printField("""
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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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printField("""
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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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printField("""
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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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printField("""
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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 printField(s: String, steps: Int) {
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var field = makeField(s)
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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: List<String> = s.split("\n")
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val w = lines.map { it.length }.max()!!
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val data = Array(lines.size) { Array(w) { false } }
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// workaround
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for (i in data.indices) {
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data[i] = Array(w) { false }
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for (j in data[i].indices)
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data[i][j] = false
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}
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for (line in lines.indices) {
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for (x in lines[line].indices) {
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val c = lines[line][x]
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data[line][x] = c == '*'
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}
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}
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return Field(w, lines.size) { i, j -> data[i][j] }
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}
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