pgoultiaev/aoc2017

package main

import (
    "fmt"
    "io/ioutil"
)

// from http://adventofcode.com/2017/day/1

func main() {
    buf, err := ioutil.ReadFile("1.txt")
    if err != nil {
        panic(err)
    }

    s := string(buf)
    l := len(s)

    fmt.Printf("Part one total sum = %d\n", solve(s, 1))
    fmt.Printf("Part two total sum = %d\n", solve(s, l/2))
}

func solve(input string, offset int) int {
    sum := 0
    for i := range input {
        curr := input[i]
        next := input[(i+offset)%len(input)]

        if curr == next {
            sum += int(curr - '0')
        }
    }
    return sum
}