using tee reader instead of seeking; use stdin for input

2024/day01.go

@@ -2,9 +2,9 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io"
-	"log"
 	"os"
 	"sort"
 )
@@ -53,13 +53,9 @@ func part2(r io.Reader) string {
 }
 
 func main() {
-	f, err := os.Open("day01.txt")
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer f.Close()
+	buf := new(bytes.Buffer)
+	tee := io.TeeReader(os.Stdin, buf)
 
-	fmt.Println(part1(f))
-	f.Seek(0, 0)
-	fmt.Println(part2(f))
+	fmt.Println(part1(tee))
+	fmt.Println(part2(buf))
 }