129 lines
2.8 KiB
Go
129 lines
2.8 KiB
Go
package main
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import (
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"bufio"
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"fmt"
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"os"
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"strconv"
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"time"
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)
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func mustAtoi(line string) int {
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i, _ := strconv.Atoi(line)
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return i
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}
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func main() {
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start := time.Now()
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partOne()
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duration := time.Since(start)
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partTwo()
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duration2 := time.Since(start)
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fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration)
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}
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func makeScanner(test bool) *bufio.Scanner {
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var f *os.File
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if test {
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f, _ = os.Open("inputs/testinput")
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} else {
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f, _ = os.Open("inputs/input")
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}
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reader := bufio.NewReader(f)
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return bufio.NewScanner(reader)
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}
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type room struct {
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row int
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col int
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distance int
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cost int
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}
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func partOne() {
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scanner := makeScanner(false)
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grid := [100][100]room{}
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col := 0
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for scanner.Scan() {
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line := scanner.Text()
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for row, v := range line {
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r := room{
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distance: 1000,
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cost: mustAtoi(string(v)),
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}
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grid[row][col] = r
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}
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col++
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}
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grid[0][0].distance = 0
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for row := 0; row < 100; row++ {
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for col := 0; col < 100; col++ {
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if col+1 < 100 {
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d := grid[row][col+1].distance
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// if the cost of the space is less than the current known distance, this is the best route there
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if d > grid[row][col+1].cost+grid[row][col].distance {
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grid[row][col+1].distance = grid[row][col].distance + grid[row][col+1].cost
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}
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}
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if row+1 < 100 {
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d := grid[row+1][col].distance
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// if the cost of the space is less than the current known distance, this is the best route there
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if d > grid[row+1][col].cost+grid[row][col].distance {
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grid[row+1][col].distance = grid[row][col].distance + grid[row+1][col].cost
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}
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}
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}
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}
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fmt.Println(grid[99][99].distance)
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}
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func partTwo() {
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scanner := makeScanner(false)
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width := 100
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scale := 5
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len := width * scale
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grid := [500][500]room{}
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col := 0
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for scanner.Scan() {
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line := scanner.Text()
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for row, v := range line {
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for i := 0; i < scale; i++ {
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for j := 0; j < scale; j++ {
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cost := mustAtoi(string(v)) + i + j
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if cost > 9 {
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cost = ((mustAtoi(string(v)) + i + j) % 10) + 1
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}
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grid[row+i*width][col+j*width] = room{
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row: row + i*width,
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col: col + j*width,
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distance: 100000,
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cost: cost,
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}
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}
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}
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}
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col++
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}
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grid[0][0].distance = 0
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for row := 0; row < len; row++ {
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for col := 0; col < len; col++ {
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// if the cost of the space is less than the current known distance, this is the best route there
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if col+1 < len {
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if grid[row][col+1].distance > grid[row][col+1].cost+grid[row][col].distance {
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grid[row][col+1].distance = grid[row][col].distance + grid[row][col+1].cost
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}
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}
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if row+1 < len {
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if grid[row+1][col].distance > grid[row+1][col].cost+grid[row][col].distance {
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grid[row+1][col].distance = grid[row][col].distance + grid[row+1][col].cost
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}
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}
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}
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}
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fmt.Println(grid[width*scale-1][width*scale-1])
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}
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