156 lines
3.0 KiB
Go
156 lines
3.0 KiB
Go
package main
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import (
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"fmt"
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"log"
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"os"
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"strconv"
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)
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const (
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MaxInt = int(^uint(0) >> 1)
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MinInt = -MaxInt - 1
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)
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var timeMachine *TimeMachine
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func main() {
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if len(os.Args) < 2 {
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fmt.Println("Usage: day11 <serial #>")
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os.Exit(1)
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}
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timeMachine = &TimeMachine{
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serial: Atoi(os.Args[1]),
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fuelLevels: make(map[string]int),
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}
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timeMachine.fillGrid()
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part1()
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part2()
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}
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func part1() {
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top := MinInt
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topX, topY := 0, 0
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for i := 1; i < 300; i++ {
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for j := 1; j < 300; j++ {
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w := timeMachine.getSquareFuelLevel(i, j, 3)
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if w > top {
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top = w
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topX, topY = i, j
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}
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}
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}
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fmt.Printf("%d,%d : %d\n", topX, topY, top)
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fmt.Println("= Part 1 =")
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timeMachine.printSquare(topX, topY, 3)
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}
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func part2() {
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top := MinInt
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topX, topY, topS := 1, 1, 1
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for i := 1; i <= 300; i++ {
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for j := 1; j <= 300; j++ {
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maxSize := 300 - (i - 1)
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if i < j {
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maxSize = 300 - (j - 1)
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}
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for s := 1; s <= maxSize; s++ {
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wrk := timeMachine.getSquareFuelLevel(i, j, s)
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if wrk > top {
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top = wrk
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topX, topY, topS = i, j, s
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}
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}
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}
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}
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fmt.Println("= Part 2 =")
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fmt.Printf("%d,%d,%d : %d\n", topX, topY, topS, top)
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}
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type TimeMachine struct {
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serial int
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fuelLevels map[string]int
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}
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func (t *TimeMachine) printSquare(x, y, size int) {
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for j := y; j < y+size; j++ {
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for i := x; i < x+size; i++ {
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fmt.Printf("%2d ", t.getSquareFuelLevel(i, j, 1))
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}
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fmt.Println("")
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}
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}
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func (t *TimeMachine) fillGrid() {
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for i := 1; i <= 300; i++ {
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for j := 1; j <= 300; j++ {
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t.fuelLevels[t.getKeyForSquare(i, j, 1)] = t.calcFuelLevel(i, j)
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}
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}
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}
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func (t *TimeMachine) getKeyForSquare(x, y, size int) string {
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bx := strconv.Itoa(x)
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by := strconv.Itoa(y)
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bs := strconv.Itoa(size)
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return bx + "," + by + "," + bs
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}
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func (t *TimeMachine) getSquareFuelLevel(x, y, size int) int {
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k := t.getKeyForSquare(x, y, size)
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if v, ok := t.fuelLevels[k]; ok {
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return v
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}
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if size == 1 {
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// We shouldn't be here if we filled the grid before running
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return 0
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}
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var ret int
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ret = t.getSquareFuelLevel(x, y, size-1)
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// Add the right-most cells
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for i := 0; i < size; i++ {
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ret += t.calcFuelLevel(x+(size-1), y+i)
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}
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// Add the bottom cells
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for i := 0; i < size-1; i++ {
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ret += t.calcFuelLevel(x+i, y+(size-1))
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}
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t.fuelLevels[k] = ret
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return ret
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}
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// calcFuelLevel calculates one cells fuel level
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func (t *TimeMachine) calcFuelLevel(x, y int) int {
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rackId := x + 10
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startingLevel := rackId * y
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currLevel := startingLevel + t.serial
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currLevel *= rackId
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var ret int
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if currLevel < 100 {
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ret = -5
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} else {
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ret = ((currLevel / 100) % 10) - 5
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}
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return ret
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}
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// calcSquareFuelLevel calculates all cells from x, y -> x+size, y+size
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func (t *TimeMachine) calcSquareFuelLevel(x, y, size int) int {
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var ret int
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for i := 0; i < size; i++ {
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for j := 0; j < size; j++ {
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ret += t.calcFuelLevel(x+i, y+j)
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}
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}
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return ret
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}
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func Atoi(i string) int {
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var ret int
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var err error
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if ret, err = strconv.Atoi(i); err != nil {
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log.Fatal("Invalid Atoi")
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}
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return ret
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}
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