81 lines
1.9 KiB
Go
81 lines
1.9 KiB
Go
package day_01
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import (
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"fmt"
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"regexp"
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"strings"
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"git.rpjosh.de/RPJosh/go-logger"
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"rpjosh.de/adventOfCode/pkg/utils"
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)
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type Day struct{}
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// findFirstAndLastNumber finds the first and last occurence of a number by the given regex
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// expression for the number (within a match group).
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// If the found string value is present in the map, the mapped value is used
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func (d *Day) findFirstAndLastNumber(in string, regex string, stringMap map[string]int) int {
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// Build regex to get the first and last number in the string (because of greediness we get the last number)
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regexFirst := regexp.MustCompile(`^.*?` + regex + `.*`)
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regexLast := regexp.MustCompile(`^.*` + regex)
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count := 0
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for _, val := range strings.Split(in, "\n") {
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if val == "" {
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continue
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}
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matchesFirst := regexFirst.FindStringSubmatch(val)
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matchesLast := regexLast.FindStringSubmatch(val)
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// We expect exactly at least one match
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if len(matchesFirst) < 1 {
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logger.Fatal("Failed to get at least one number (got %d): %q", len(matchesFirst), val)
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}
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str := d.replaceDigitByInt(matchesFirst[1], stringMap)
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if len(matchesLast) > 1 {
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str += d.replaceDigitByInt(matchesLast[1], stringMap)
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}
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count += utils.ToInt(str)
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}
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return count
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}
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func (d *Day) replaceDigitByInt(val string, stringMap map[string]int) string {
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if v, exists := stringMap[val]; exists {
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return fmt.Sprintf("%d", v)
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}
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return val
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}
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func (d *Day) Part1(in string) string {
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return fmt.Sprintf("%d", d.findFirstAndLastNumber(in, `(\d)`, make(map[string]int)))
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}
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func (d *Day) Part2(in string) string {
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digist := map[string]int{
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"one": 1,
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"two": 2,
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"three": 3,
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"four": 4,
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"five": 5,
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"six": 6,
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"seven": 7,
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"eight": 8,
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"nine": 9,
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}
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// Build regex string by looping through all digists
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regex := `(\d`
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for k, _ := range digist {
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regex += "|" + k
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}
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regex += ")"
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return fmt.Sprintf("%d", d.findFirstAndLastNumber(in, regex, digist))
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}
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