github.com/agrigoryan/aoc_2023_go@v0.0.0-20231216221323-4ace361ec685/day4/d4p2.go (about)

     1  package day4
     2  
     3  import (
     4  	"fmt"
     5  	"slices"
     6  	"strings"
     7  
     8  	"github.com/agrigoryan/aoc_2023_go/aocutils"
     9  )
    10  
    11  func d4p2(input string) int {
    12  	lines := strings.Split(input, "\n")
    13  	counts := make([]int, len(lines))
    14  	for i := 0; i < len(lines); i++ {
    15  		counts[i] = 1
    16  	}
    17  
    18  	trimSpaces := aocutils.Mapper(func(str string) string { return strings.TrimSpace(str) })
    19  	filterEmpty := aocutils.Filterer(func(str string) bool { return len(str) > 0 })
    20  
    21  	for i, line := range strings.Split(input, "\n") {
    22  		ticket := strings.Split(line, ":")[1]
    23  		parts := strings.Split(ticket, "|")
    24  		winningNumbers := filterEmpty(trimSpaces(strings.Split(parts[0], " ")))
    25  		numbers := filterEmpty(trimSpaces(strings.Split(parts[1], " ")))
    26  		matches := 0
    27  		for _, num := range numbers {
    28  			if slices.Contains(winningNumbers, num) {
    29  				matches += 1
    30  			}
    31  		}
    32  		for j := i + 1; j <= i+matches; j++ {
    33  			counts[j] += counts[i]
    34  		}
    35  	}
    36  	numTickets := 0
    37  	for _, num := range counts {
    38  		numTickets += num
    39  	}
    40  	fmt.Println(numTickets)
    41  	return numTickets
    42  }