advent_of_code_2025/2/solve_1.go

package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"
)

func is_invalid(id int) bool {
	idstr := strconv.Itoa(id)
	size_idstr := len(idstr)
	if (size_idstr % 2) != 0 {
		return false
	}
	return idstr[:size_idstr/2] == idstr[size_idstr/2:]
}

func count_invalids(lb, ub int) int{
	res := 0
	for i:=lb; i <= ub; i++ {
		if is_invalid(i) {
			res += i
		}
	}
	return res
}


func main() {
	fmt.Println("Advent of Code 2025 - Day 2 - Part 1")
	f, _ := os.ReadFile("2/input")
	l := strings.Split(string(f), ",")
	var ranges []string
	var lower_bound, upper_bound int
	res:=0
	for _,value := range l {
		ranges = strings.Split(value,"-")
		lower_bound, _ = strconv.Atoi(ranges[0])
		upper_bound, _ = strconv.Atoi(ranges[1])
		res += count_invalids(lower_bound, upper_bound)
	}
	fmt.Println(res)
}