advent_of_code_2025/2/solve_2.go

package main

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


func is_kinvalid(id string, k int) bool{
	size_idstr := len(id)
	if (size_idstr % k) != 0 {
		return false
	}

	l:= size_idstr / k
	
	for i:= 0; i+l < size_idstr ; i+=l {
		if id[i : i+l] != id[i+l : i+2*l]{
			return false
		}
	}
	return true
}

func is_invalid(id int) bool {
	idstr := strconv.Itoa(id)
	size_idstr := len(idstr)
	for k:=2; k <= size_idstr; k++{
		if is_kinvalid(idstr, k) {
			return true
		}
	}	
	return false
}

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 2")
	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)
}