110 lines
1.7 KiB
Go
110 lines
1.7 KiB
Go
package main
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import (
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"fmt"
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"strconv"
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"strings"
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)
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type Day2Input [][]int64
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func Day2Parse(lines []string) (Day2Input, error) {
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rows := make([][]int64, len(lines))
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for i, line := range lines {
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levelsCount := strings.Count(line, " ") + 1
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rows[i] = make([]int64, levelsCount)
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for j, level := range strings.Split(line, " ") {
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number, err := strconv.ParseInt(level, 10, 0)
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if err != nil {
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return nil, err
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}
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rows[i][j] = number
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}
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}
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return rows, nil
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}
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func absInt(value int64) int64 {
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if value < 0 {
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return -value
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} else {
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return value
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}
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}
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func Day2IsReportSafe(report []int64) bool {
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increasing := false
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decreasing := false
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for i := range len(report)-1 {
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if report[i+1] >= report[i] {
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increasing = true
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}
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if report[i+1] <= report[i] {
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decreasing = true
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}
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if absInt(report[i+1] - report[i]) >= 4 {
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return false
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}
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if increasing && decreasing {
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return false
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}
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}
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return !(increasing && decreasing) && (increasing || decreasing)
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}
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func Day2Part1(lines []string) error {
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input, err := Day2Parse(lines)
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if err != nil {
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return err
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}
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answer := 0
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for _, row := range input {
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if Day2IsReportSafe(row) {
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answer += 1
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}
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}
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fmt.Println(answer)
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return nil
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}
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func DeleteAtIndex(slice []int64, index int) []int64 {
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result := make([]int64, len(slice))
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copy(result, slice)
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return append(result[:index], result[index+1:]...)
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}
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func Day2Part2(lines []string) error {
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input, err := Day2Parse(lines)
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if err != nil {
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return err
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}
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answer := 0
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for _, row := range input {
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if Day2IsReportSafe(row) {
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answer += 1
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continue
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}
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for i := range len(row) {
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if Day2IsReportSafe(DeleteAtIndex(row, i)) {
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answer += 1
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break
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}
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}
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}
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fmt.Println(answer)
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return nil
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}
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