74 lines
2.2 KiB
Kotlin
74 lines
2.2 KiB
Kotlin
package at.petrak.hex.hexes
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/**
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* Sequence of angles to define a pattern traced.
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*/
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@JvmRecord
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data class HexPattern(val startDir: HexDir, val angles: MutableList<HexAngle> = arrayListOf()) {
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/**
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* @return True if it successfully appended, false if not.
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*/
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fun tryAppendDir(newDir: HexDir): Boolean {
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// Two restrictions:
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// - No adding a pos/dir pair we previously added
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// - No backtracking
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val linesSeen = mutableSetOf<Pair<HexCoord, HexDir>>()
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var compass = this.startDir
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var cursor = HexCoord.Origin
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for (a in this.angles) {
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linesSeen.add(Pair(cursor, compass))
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cursor += compass
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compass *= a
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}
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val potentialNewLine = Pair(cursor, newDir)
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if (potentialNewLine in linesSeen) return false
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val nextAngle = newDir - compass
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if (nextAngle == HexAngle.BACK) return false
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this.angles.add(nextAngle)
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return true
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}
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@JvmOverloads
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fun positions(start: HexCoord = HexCoord.Origin): List<HexCoord> {
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val out: ArrayList<HexCoord> = ArrayList(this.angles.size + 2)
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out.add(start)
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var compass: HexDir = this.startDir
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var cursor = start
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for (a in this.angles) {
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cursor += compass
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out.add(cursor)
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compass *= a
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}
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out.add(cursor.shiftedBy(compass))
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return out
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}
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// Terrible shorthand method for easy matching
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fun anglesSignature(): String {
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return buildString {
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for (a in this@HexPattern.angles) {
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append(
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when (a) {
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HexAngle.FORWARD -> "w"
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HexAngle.RIGHT -> "e"
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HexAngle.RIGHT_BACK -> "d"
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HexAngle.BACK -> "s"
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HexAngle.LEFT_BACK -> "a"
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HexAngle.LEFT -> "q"
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}
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)
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}
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}
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}
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override fun toString(): String = buildString {
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append("[HexPattern ")
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append(this@HexPattern.startDir)
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append(", ")
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append(this@HexPattern.anglesSignature())
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append("]")
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}
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} |