Added the first days

2021/01/second.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+)
+
+func main() {
+	f, err := os.Open("input")
+	if err != nil {
+		log.Fatalf("%+v", err)
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	scanner.Split(bufio.ScanLines)
+
+	scanner.Scan()
+	A, err := strconv.Atoi(scanner.Text())
+	if err != nil {
+		log.Fatalf("%+v", err)
+	}
+	scanner.Scan()
+	B, err := strconv.Atoi(scanner.Text())
+	if err != nil {
+		log.Fatalf("%+v", err)
+	}
+	A += B
+	scanner.Scan()
+	C, err := strconv.Atoi(scanner.Text())
+	if err != nil {
+		log.Fatalf("%+v", err)
+	}
+	B += C
+	A += C
+
+	result := 0
+
+	for scanner.Scan() {
+		D, err := strconv.Atoi(scanner.Text())
+		if err != nil {
+			log.Fatalf("%+v", err)
+		}
+		C += D
+		B += D
+		if B > A {
+			result++
+		}
+		A = B
+		B = C
+		C = D
+	}
+	fmt.Println(result)
+}