61 lines
1.0 KiB
Go
61 lines
1.0 KiB
Go
package main
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import (
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"strconv"
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"strings"
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"github.com/StevanFreeborn/advent-of-code-2025/internal/file"
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)
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const SeparatorCharacter = ","
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const RangeSeparatorCharacter = "-"
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type Range struct {
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Start int64
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End int64
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}
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func SolvePartOne(filePath string) int64 {
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input := file.ReadAllText(filePath)
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strRanges := strings.SplitSeq(input, SeparatorCharacter)
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rngs := []Range{}
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for r := range strRanges {
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parts := strings.Split(strings.TrimSpace(r), "-")
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start, _ := strconv.ParseInt(parts[0], 10, 64)
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end, _ := strconv.ParseInt(parts[1], 10, 64)
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rng := Range{
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Start: start,
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End: end,
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}
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rngs = append(rngs, rng)
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}
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total := int64(0)
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for _, rng := range rngs {
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for id := rng.Start; id <= rng.End; id++ {
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idStr := strconv.FormatInt(id, 10)
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idLength := len(idStr)
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if idLength%2 != 0 {
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continue
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}
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midpoint := idLength / 2
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firstHalf := idStr[:midpoint]
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secondHalf := idStr[midpoint:]
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if firstHalf != secondHalf {
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continue
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}
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total += id
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}
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}
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return total
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}
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