From 5f5cff83371cb1c4f213de55147eb9646c444b8d Mon Sep 17 00:00:00 2001
From: gergo <kiss.gergely@gmail.com>
Date: Sun, 25 Dec 2022 10:09:58 +0100
Subject: [PATCH] day 25

---
 src/main/kotlin/me/gergo/Aoc25.kt |  40 +++++++++++
 src/main/resources/input25.txt    | 108 ++++++++++++++++++++++++++++++
 2 files changed, 148 insertions(+)
 create mode 100644 src/main/kotlin/me/gergo/Aoc25.kt
 create mode 100644 src/main/resources/input25.txt

diff --git a/src/main/kotlin/me/gergo/Aoc25.kt b/src/main/kotlin/me/gergo/Aoc25.kt
new file mode 100644
index 0000000..6a516bf
--- /dev/null
+++ b/src/main/kotlin/me/gergo/Aoc25.kt
@@ -0,0 +1,40 @@
+package me.gergo
+
+import java.io.File
+import kotlin.math.pow
+
+fun main() {
+    val snafuNumbers = File("src/main/resources/input25.txt").readLines()
+
+    val result1 = decimalToSnafu(snafuNumbers.map(::snafuToDecimal).sum())
+
+    println("SNAFU number to supply to the console: $result1")
+}
+
+private fun snafuToDecimal(value: String): Long {
+    var result = 0L
+    for (i in value.indices) {
+        val v = when (value[value.length - 1 - i]) {
+            '=' -> -2
+            '-' -> -1
+            '0' -> 0
+            '1' -> 1
+            '2' -> 2
+            else -> throw NumberFormatException(value)
+        }
+        result += 5.0.pow(i).toLong() * v
+    }
+    return result
+}
+
+private const val Digits = "=-012"
+private fun decimalToSnafu(value: Long): String {
+    var result = ""
+    var rem = value
+    while (rem > 0) {
+        rem += 2 // Shift because of the negative values
+        result = "${Digits[(rem % 5).toInt()]}$result"
+        rem /= 5
+    }
+    return result
+}
\ No newline at end of file
diff --git a/src/main/resources/input25.txt b/src/main/resources/input25.txt
new file mode 100644
index 0000000..b5d3df6
--- /dev/null
+++ b/src/main/resources/input25.txt
@@ -0,0 +1,108 @@
+2=11
+22=01--
+1=2=0-111-0
+1=121=--0
+222==1=2001=21121=
+2-22221
+1==--1012=11-
+10-==111--001
+2102=20-012-20
+11-==002
+1=1=-0=
+21-1-=1111--
+10201==202=0-22=2-2
+2--10==11211111
+10==--0=2=220
+1-0210-0=2
+11--1=-=201-22==
+210=102-
+1=1121-=2222001
+110201=2-==22
+1=020=-2020111
+1-1-0-=022-01120
+2==01-2111210=
+1=0---1=222111=
+1=22=--20=
+202--0--1=100
+12--2-01--2222=1
+1==-==2
+12111
+1-12
+22
+2-0-0=-=00=220--1=
+1=-210=02-11=
+21=2-01-11-02--02
+10-2-20=01-01-=
+1=-11=2-1==-1=-11=
+1211--22110
+1020
+1121==2002===
+2=1-02=
+1-
+2=11221-2101
+110-0--11
+1112---11-
+1---=-2
+1022=0121==--02
+1=2-==2
+2-=010-02=2-
+11-00-2=2=2202
+1=12-1-0==1--
+2-==0=2
+1-=-0=-0--=
+201122--1220=
+1=---002
+2=2=210012--12
+1==0=2=
+201=1==-=1120122
+2=02000
+1=02==--=1100=-
+1=-01=2-21-=-10
+1=211
+1-10=101-00=021=1
+2-0
+1--=01201200010==
+1-1020--=-=11==1
+2=1=
+1=-
+1-10202=0=12-1
+100
+2--1=0-0-10
+2122=12
+1-0-=-=0=21202
+10111
+2200112-122=2=0-=1
+2--10-22=110==2-000
+1=1-010-1=11-000020-
+1=2=---22
+1=
+12-0==
+1=0
+1==0==-=1=2--
+1--211-00-2=
+1--0
+2=-0
+1-10=---=-=1=
+2=1
+1=-0=021-20
+201=01=
+1=0==1
+1---0212-=
+1==21-=121=
+21-=1020-
+1002-102=2-212=0-0
+22-=--20
+22=
+10-=-=1-2=
+1--=-0
+102=000021
+10===
+100100-02
+2-=00=20=12=-
+1=2=01=02
+1=101---0==
+1-=1001--=22-=00
+11=21220-111011-
+20
+2=2-=-22-=21-1210
+1=1110