Rename main.go to day01.go

2017/day01/day01.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"strconv"
+)
+
+func main() {
+	inp := StdinToString()
+	part1(inp)
+	part2(inp)
+}
+
+func part1(inp string) {
+	sum := 0
+	for k := range inp {
+		tstIdx := getCompareIndex(k, 1, len(inp))
+		sum += getCompareResult(inp[k], inp[tstIdx])
+	}
+	fmt.Println("Part 1:", sum)
+}
+
+func part2(inp string) {
+	sum := 0
+	for k := range inp {
+		tstIdx := getCompareIndex(k, (len(inp) / 2), len(inp))
+		sum += getCompareResult(inp[k], inp[tstIdx])
+	}
+	fmt.Println("Part 2:", sum)
+}
+
+func getCompareIndex(curr, add, max int) int {
+	return int(math.Mod(float64(curr+add), float64(max)))
+}
+
+func getCompareResult(c1, c2 byte) int {
+	if c1 != c2 {
+		return 0
+	}
+	return Atoi(string(c1))
+}
+
+func StdinToString() string {
+	var input string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input += scanner.Text()
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}