package main
import (
"fmt"
"os"
"strconv"
"strings"
)
func getMoves(input string) (int, []string) {
var crateRows int
//Count on which row there's a double linebreak
for i, ch := range input {
if ch == '\n' && input[i+1] != '\n' {
crateRows++
}
if ch == '\n' && input[i+1] == '\n' {
break
}
}
//Return number of rows and the moves
moves := strings.Split(input, "\n")[crateRows+2:]
return crateRows, moves
}
// Function to get the letters from each "crate"
func splitToStacks(input string, crateRows int) [][]string {
rows := strings.Split(input, "\n")[0:crateRows]
crateRow := strings.Split(input, "\n")[crateRows]
numCrates, _ := strconv.Atoi(string(crateRow[len(crateRow)-2]))
stacks := make([][]string, numCrates+1)
for i := len(rows) - 1; i >= 0; i-- {
k := 1
for j := 1; j < len(rows[0])-1; j += 4 {
if string(rows[i][j]) != " " {
stacks[k] = append(stacks[k], string(rows[i][j]))
}
k++
}
}
return stacks
}
func splitMoves(moves []string) [][]int {
toret := make([][]int, len(moves))
for i := 0; i < len(moves); i++ {
//Split each move into numbers
move := strings.Split(moves[i], " ")
tempNum, _ := strconv.Atoi(move[1])
tempFrom, _ := strconv.Atoi(move[3])
tempTo, _ := strconv.Atoi(move[5])
//Save the numbers to an array
toret[i] = append(toret[i], tempNum)
toret[i] = append(toret[i], tempFrom)
toret[i] = append(toret[i], tempTo)
}
return toret
}
func MakeMoves1(stacks [][]string, moves [][]int) [][]string {
for i := 0; i < len(moves); i++ {
num := moves[i][0]
from := moves[i][1]
to := moves[i][2]
//Move the correct number of letters from the "from" stack to the "to" stack
for j := 0; j < num; j++ {
stacks[to] = append(stacks[to], stacks[from][len(stacks[from])-1])
stacks[from] = stacks[from][:len(stacks[from])-1]
}
}
return stacks
}
func MakeMoves2(stacks [][]string, moves [][]int) [][]string {
for i := 0; i < len(moves); i++ {
num := moves[i][0]
from := moves[i][1]
to := moves[i][2]
//Move letters from the "from" stack to the "to" stack in batches on "num"
stacks[to] = append(stacks[to], stacks[from][len(stacks[from])-num:]...)
stacks[from] = stacks[from][:len(stacks[from])-num]
}
return stacks
}
func printLast(stacks [][]string) {
for i := 1; i < len(stacks); i++ {
fmt.Print(stacks[i][len(stacks[i])-1])
}
}
func main() {
input, _ := os.ReadFile("input.txt")
inputString := string(input)
//Find separator between crates and moves
crateRows, tempmoves := getMoves(inputString)
//Get the crate letters into an array per collumn
stacks := splitToStacks(inputString, crateRows)
//Split moverows into pure numbers
moves := splitMoves(tempmoves)
//Create stack for first method
stacks1 := MakeMoves1(stacks, moves)
//Need to recreate stacks because MakeMoves1 changes the original
stacks = splitToStacks(inputString, crateRows)
//Create stack for second method
stacks2 := MakeMoves2(stacks, moves)
//Print last element of each stack
printLast(stacks1)
fmt.Println()
printLast(stacks2)
}
