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| 1 | +package main |
| 2 | + |
| 3 | +import "fmt" |
| 4 | + |
| 5 | +func main() { |
| 6 | + SerialNumber := 5791 |
| 7 | + grid := [300][300]int{} |
| 8 | + cellPower(&grid, SerialNumber) |
| 9 | + // partOne(grid) |
| 10 | + partTwo(grid) |
| 11 | +} |
| 12 | + |
| 13 | +func partOne(grid [300][300]int) { |
| 14 | + maxPower := 0 |
| 15 | + coords := "" |
| 16 | + for row := range grid { |
| 17 | + for cell := range grid[row] { |
| 18 | + power := calculatePower(grid, row, cell) // Calculate the power level on a 3x3 square starting here |
| 19 | + if power > maxPower { |
| 20 | + maxPower = power |
| 21 | + coords = fmt.Sprintf("%d,%d", cell+1, row+1) |
| 22 | + } |
| 23 | + } |
| 24 | + } |
| 25 | + fmt.Printf("Part 1 | Max at %s with power %d\n", coords, maxPower) |
| 26 | +} |
| 27 | + |
| 28 | +func partTwo(grid [300][300]int) { |
| 29 | + maxPower := 0 |
| 30 | + coords := "" |
| 31 | + size := 0 |
| 32 | + for row := range grid { |
| 33 | + for cell := range grid[row] { |
| 34 | + maxSize := min(299-cell, 299-row) // Maximum size the square can have |
| 35 | + // fmt.Printf("%d,%d, max size %d\n", cell+1, row+1, maxSize) |
| 36 | + for s := range maxSize { |
| 37 | + power := calculatePowerWithSize(grid, row, cell, s) // Calculate the power level on a 3x3 square starting here |
| 38 | + if power > maxPower { |
| 39 | + maxPower = power |
| 40 | + coords = fmt.Sprintf("%d,%d", cell+1, row+1) |
| 41 | + size = s |
| 42 | + } |
| 43 | + } |
| 44 | + } |
| 45 | + } |
| 46 | + fmt.Printf("Part 2 | Max at %s with power %d and size %d\n", coords, maxPower, size) |
| 47 | +} |
| 48 | + |
| 49 | +func cellPower(grid *[300][300]int, SerialNumber int) { |
| 50 | + // Remember the coordinates have to be +1, because arrays start at 0. |
| 51 | + for row := range grid { |
| 52 | + for cell := range grid[row] { |
| 53 | + rackID := (cell + 1) + 10 |
| 54 | + powerLevel := rackID * (row + 1) |
| 55 | + add := powerLevel + SerialNumber |
| 56 | + value := add * rackID |
| 57 | + hundreds := (value / 100) % 10 |
| 58 | + result := hundreds - 5 |
| 59 | + grid[row][cell] = result |
| 60 | + } |
| 61 | + } |
| 62 | +} |
| 63 | + |
| 64 | +func calculatePower(grid [300][300]int, row, cell int) int { |
| 65 | + s := 0 |
| 66 | + // Bounds |
| 67 | + if (row+2 < 300) && (cell+2 < 300) { |
| 68 | + for y := 0; y < 3; y++ { |
| 69 | + for x := 0; x < 3; x++ { |
| 70 | + s += grid[row+y][cell+x] |
| 71 | + } |
| 72 | + } |
| 73 | + } |
| 74 | + return s |
| 75 | +} |
| 76 | + |
| 77 | +func calculatePowerWithSize(grid [300][300]int, row, cell, size int) int { |
| 78 | + s := 0 |
| 79 | + // Bounds |
| 80 | + for y := 0; y < size; y++ { |
| 81 | + for x := 0; x < size; x++ { |
| 82 | + s += grid[row+y][cell+x] |
| 83 | + } |
| 84 | + } |
| 85 | + return s |
| 86 | +} |
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