Percolation/Site percolation: Difference between revisions
Added Kotlin
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(Added Kotlin) |
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Line 1,096:
p = 0.9 ⇛ f = 1.000
p = 1.0 ⇛ f = 1.000</pre>
=={{header|Kotlin}}==
{{trans|C}}
<lang scala>// version 1.2.10
import java.util.Random
val rand = Random()
const val RAND_MAX = 32767
const val NUL = '\u0000'
val x = 15
val y = 15
var grid = StringBuilder((x + 1) * (y + 1) + 1)
var cell = 0
var end = 0
var m = 0
var n = 0
fun makeGrid(p: Double) {
val thresh = (p * RAND_MAX).toInt()
m = x
n = y
grid.setLength(0) // clears grid
grid.setLength(m + 1) // sets first (m + 1) chars to NUL
end = m + 1
cell = m + 1
for (i in 0 until n) {
for (j in 0 until m) {
val r = rand.nextInt(RAND_MAX + 1)
grid.append(if (r < thresh) '+' else '.')
end++
}
grid.append('\n')
end++
}
grid[end - 1] = NUL
end -= ++m // end is the index of the first cell of bottom row
}
fun ff(p: Int): Boolean { // flood fill
if (grid[p] != '+') return false
grid[p] = '#'
return p >= end || ff(p + m) || ff(p + 1) || ff(p - 1) || ff(p - m)
}
fun percolate(): Boolean {
var i = 0
while (i < m && !ff(cell + i)) i++
return i < m
}
fun main(args: Array<String>) {
makeGrid(0.5)
percolate()
println("$x x $y grid:")
println(grid)
println("\nrunning 10,000 tests for each case:")
for (ip in 0..10) {
val p = ip / 10.0
var cnt = 0
for (i in 0 until 10_000) {
makeGrid(p)
if (percolate()) cnt++
}
println("p = %.1f: %.4f".format(p, cnt / 10000.0))
}
}</lang>
Sample output:
<pre>
15 x 15 grid:
.#.##..##..##.#
.#.##..#..###.#
.....++.###.#..
....+.+..###...
+.+.+..+...####
..+.+.+..#..##.
++...+..###.###
+++.+.+.#.###.#
+..++...#.#.###
++..+.+.#..+...
.+.+.+++..+.+++
...++.+.++++...
+..+..+.++.++.+
+...++..++...+.
..+.+++..+..++.
running 10,000 tests for each case:
p = 0.0: 0.0000
p = 0.1: 0.0000
p = 0.2: 0.0000
p = 0.3: 0.0000
p = 0.4: 0.0038
p = 0.5: 0.0998
p = 0.6: 0.5617
p = 0.7: 0.9558
p = 0.8: 0.9998
p = 0.9: 1.0000
p = 1.0: 1.0000
</pre>
=={{header|Perl 6}}==
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