Advent of Code 2020 is Complete!

2020/day23/main.go

@@ -17,7 +17,7 @@ func init() {
 }
 
 func main() {
-	fmt.Println("# Day 22")
+	fmt.Println("# Day 23")
 	inp := h.StdinToString()
 
 	solve(inp, h.Atoi(h.OptArgNumber(1, "2")))

2020/day24/main.go

@@ -18,7 +18,7 @@ func init() {
 }
 
 func main() {
-	fmt.Println("# Day 22")
+	fmt.Println("# Day 24")
 	inp := h.StdinToStringSlice()
 
 	solve(inp, h.Atoi(h.OptArgNumber(1, "2")))

2020/day25/input

@@ -0,0 +1,2 @@
+3248366
+4738476

2020/day25/main.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func init() {
+}
+
+func main() {
+	fmt.Println("# Day 25")
+	inp := h.StdinToStringSlice()
+
+	solve(inp, h.Atoi(h.OptArgNumber(1, "2")))
+}
+
+func solve(inp []string, part int) {
+	card, door := 7, 7
+	cardPub := h.Atoi(inp[0])
+	doorPub := h.Atoi(inp[1])
+	var cardLoops, doorLoops int
+	cardVal, doorVal := 1, 1
+	for cardVal != cardPub {
+		cardVal = loop(cardVal, card)
+		cardLoops++
+	}
+	for doorVal != doorPub {
+		doorVal = loop(doorVal, door)
+		doorLoops++
+	}
+	fmt.Println("Card Loop Size:", cardLoops)
+	fmt.Println("Door Loop Size:", doorLoops)
+	ans := 1
+	for i := 0; i < cardLoops; i++ {
+		ans = loop(ans, doorVal)
+	}
+	fmt.Println("Answer:", ans)
+}
+
+const div = 20201227
+
+func loop(v, subject int) int {
+	v = v * subject
+	return v % div
+}

2020/day25/testinput

@@ -0,0 +1,2 @@
+5764801
+17807724