Add solutions for 2023 Day 3

2023/03p1.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+
+	"aoc2023/utils"
+)
+
+type enginePart struct {
+	number             int
+	isPart             bool
+	partIdentifier     rune
+	identifierPosition coordinate
+}
+
+type coordinate struct {
+	x int
+	y int
+}
+
+func D03P1() {
+	lines := utils.ReadLines("inputs/03.txt")
+	grid := make([][]rune, len(lines))
+
+	engineParts := []enginePart{}
+
+	for i, line := range lines {
+		grid[i] = []rune(line)
+	}
+
+	currentPart := enginePart{}
+	partNumberString := ""
+	for i, line := range grid {
+		for j, char := range line {
+			if char >= '0' && char <= '9' {
+				partNumberString += string(char)
+
+				if !currentPart.isPart {
+					checkIfPartIsPart(coordinate{j, i}, grid, &currentPart)
+				}
+
+			} else if partNumberString != "" {
+				currentPart.number, _ = strconv.Atoi(partNumberString)
+
+				engineParts = append(engineParts, currentPart)
+				partNumberString = ""
+				currentPart = enginePart{}
+			}
+		}
+	}
+
+	sumOfParts := 0
+	for _, part := range engineParts {
+		if part.isPart {
+			sumOfParts += part.number
+		}
+	}
+
+	fmt.Printf("Sum of parts: %d\n", sumOfParts)
+}
+
+func checkIfPartIsPart(position coordinate, grid [][]rune, currentPart *enginePart) {
+	neighbouringGridPoisitions := []coordinate{
+		{position.x + 1, position.y + 1},
+		{position.x + 1, position.y - 1},
+		{position.x + 1, position.y},
+		{position.x - 1, position.y + 1},
+		{position.x - 1, position.y - 1},
+		{position.x - 1, position.y},
+		{position.x, position.y + 1},
+		{position.x, position.y - 1},
+	}
+	for _, neighbour := range neighbouringGridPoisitions {
+		//Check if coordinate is in grid
+		if neighbour.x < 0 || neighbour.y < 0 || neighbour.x >= len(grid) ||
+			neighbour.y >= len(grid[0]) {
+			continue
+		}
+
+		// Check if the neighbour is a number
+		if grid[neighbour.y][neighbour.x] >= '0' && grid[neighbour.y][neighbour.x] <= '9' {
+			continue
+		}
+
+		// Check if the neighbour is a full stop
+		if grid[neighbour.y][neighbour.x] == '.' {
+			continue
+		}
+
+		currentPart.partIdentifier = grid[neighbour.y][neighbour.x]
+		currentPart.identifierPosition = neighbour
+		currentPart.isPart = true
+		return
+	}
+}

2023/03p2.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+
+	"aoc2023/utils"
+)
+
+func D03P2() {
+	lines := utils.ReadLines("inputs/03.txt")
+	grid := make([][]rune, len(lines))
+
+	engineParts := []enginePart{}
+
+	for i, line := range lines {
+		grid[i] = []rune(line)
+	}
+
+	currentPart := enginePart{}
+	partNumberString := ""
+	for i, line := range grid {
+		for j, char := range line {
+			if char >= '0' && char <= '9' {
+				partNumberString += string(char)
+
+				if !currentPart.isPart {
+					checkIfPartIsPart(coordinate{j, i}, grid, &currentPart)
+				}
+
+			} else if partNumberString != "" {
+				currentPart.number, _ = strconv.Atoi(partNumberString)
+
+				engineParts = append(engineParts, currentPart)
+				partNumberString = ""
+				currentPart = enginePart{}
+			}
+		}
+	}
+
+	// Using a map prevents duplicate gear ratios
+	gearRatios := map[coordinate]int{}
+
+	for _, part := range engineParts {
+		if part.partIdentifier == '*' {
+			// Check if the other half of the gear ratio is in the list
+			for _, otherPart := range engineParts {
+				if otherPart.partIdentifier == '*' &&
+					otherPart.identifierPosition == part.identifierPosition && otherPart.number != part.number {
+
+					// Add the gear ratio to the map
+					gearRatios[part.identifierPosition] = part.number * otherPart.number
+				}
+			}
+		}
+	}
+
+	totalSumOfGearRatios := 0
+	for _, gearRatio := range gearRatios {
+		totalSumOfGearRatios += gearRatio
+	}
+
+	fmt.Printf("Sum of gear ratios: %d\n", totalSumOfGearRatios)
+}