2023 day 05

2023/05/part1/main.go

@@ -0,0 +1,81 @@
+
+package main
+
+import (
+	"bufio"
+	"os"
+	"strings"
+	"strconv"
+)
+
+func main() {
+	reader := bufio.NewReader(os.Stdin);
+
+	println("reading seeds")
+	text, _ := reader.ReadString('\n')
+	seeds := strings.Split(strings.Trim(strings.Split(text, ": ")[1], "\n"), " ");
+
+	reader.ReadString('\n')
+	mappers := [][]resMap{};
+
+	for {
+
+		line, _ := reader.ReadString('\n')
+		if len(line) < 1 {
+			break;
+		}
+		println("reading", line)
+
+		mapper := []resMap{};
+
+		for {
+			nextLine, _ := reader.ReadString('\n');
+			seedToSoil := strings.Split(strings.Trim(nextLine, "\n"), " ");
+			if len(seedToSoil) != 3 {
+				break;
+			}
+			destStart, _ := strconv.Atoi(seedToSoil[0]);
+			srcStart, _ := strconv.Atoi(seedToSoil[1]);
+			length, _ := strconv.Atoi(seedToSoil[2]);
+			mapper = append(mapper, resMap{destStart,srcStart,length})
+		}
+
+		mappers = append(mappers, mapper)
+	}
+
+	smallest := 0;
+
+	for _, seed := range seeds {
+		loc, _ := strconv.Atoi(seed)
+		newLoc := seedLoc(mappers, loc)
+		if smallest == 0 || newLoc < smallest {
+			smallest = newLoc
+		}
+	}
+
+	println(smallest)
+	
+}
+
+func seedLoc(mappers [][]resMap, source int) int {
+	for _, m := range mappers {
+		source = mapSeed(m, source)
+	}
+	return source
+}
+
+func mapSeed(soil []resMap, source int) (int) {
+	for _, m := range soil {
+		if source >= m.srcStart && source < m.srcStart + m.length {
+			return m.destStart + (source - m.srcStart)
+		}
+	}
+	return source
+}
+
+type resMap struct {
+	destStart int
+	srcStart int
+	length int
+}
+