aoc2023/day7/day7.go

package day7

import (
	"fmt"
	"log"
	"sort"
	"strconv"
	"strings"
)

type Hand struct {
	original string
	cards    []rune
	bid      int
	strength int
}

func EvalHands(lines []string) int {
	hands := []Hand{}

	/*
		1+1+1+1+1   1          1*1*1*1*1
		2+1+1+1     3          3*1*1*1
		2+2        	9          3*3
		3+1+1    		7          7*1*1
		3+2        21          7*3
		4+1        11          11*1
		5+0        13          13
	*/
	strengthConv := make([]int, 22)
	strengthConv[1] = 1
	strengthConv[3] = 2
	strengthConv[9] = 3
	strengthConv[7] = 4
	strengthConv[21] = 5
	strengthConv[11] = 6
	strengthConv[13] = 7

	for _, l := range lines {
		strength := 1
		counts := make([]int, 13)
		parts := strings.Fields(l)

		cards := []rune(parts[0])
		bid, _ := strconv.Atoi(parts[1])

		for i, card := range cards {
			switch card {
			case '2', '3', '4', '5', '6', '7', '8', '9':
				counts[card-'2']++
			case 'T':
				counts[8]++
				cards[i] = 'a'
			case 'J':
				counts[9]++
				cards[i] = 'b'
			case 'Q':
				counts[10]++
				cards[i] = 'c'
			case 'K':
				counts[11]++
				cards[i] = 'd'
			case 'A':
				counts[12]++
				cards[i] = 'e'
			default:
				log.Fatalf("invalid card: %v", card)
			}
		}

		for _, count := range counts {
			switch count {
			case 2:
				strength *= 3
			case 3:
				strength *= 7
			case 4:
				strength *= 11
			case 5:
				strength *= 13
			}
		}

		h := Hand{
			cards:    cards,
			bid:      bid,
			strength: strengthConv[strength],
		}

		hands = append(hands, h)
	}

	sort.Slice(hands, func(i, j int) bool {
		if hands[i].strength == hands[j].strength {
			for k := 0; k < 5; k++ {
				if hands[i].cards[k] != hands[j].cards[k] {
					return hands[i].cards[k] < hands[j].cards[k]
				}
			}
			return false
		} else {
			return hands[i].strength < hands[j].strength
		}
	})

	result := 0

	for i, hand := range hands {
		result += (i + 1) * hand.bid
	}

	return result
}

func EvalHandsWithJoker(lines []string) int {
	hands := []Hand{}

	/*
		1+1+1+1+1   1          1*1*1*1*1
		2+1+1+1     3          3*1*1*1
		2+2        	9          3*3
		3+1+1    		7          7*1*1
		3+2        21          7*3
		4+1        11          11*1
		5+0        13          13
	*/
	strengthConv := make([]int, 22)
	strengthConv[1] = 1  // high card
	strengthConv[3] = 2  // pair
	strengthConv[9] = 3  // two pairs
	strengthConv[7] = 4  // brelan
	strengthConv[21] = 5 // full
	strengthConv[11] = 6 // carre
	strengthConv[13] = 7 // five

	for _, l := range lines {
		strength := 1
		counts := make([]int, 13)
		parts := strings.Fields(l)

		original := parts[0]
		cards := []rune(parts[0])
		bid, _ := strconv.Atoi(parts[1])
		countJ := 0

		for i, card := range cards {
			switch card {
			case '2', '3', '4', '5', '6', '7', '8', '9':
				counts[card-'2']++
			case 'T':
				counts[8]++
				cards[i] = 'a'
			case 'J':
				/*
					counts[9]++
					cards[i] = 'b'
				*/
				cards[i] = '1' // weakest
				countJ++
			case 'Q':
				counts[10]++
				cards[i] = 'c'
			case 'K':
				counts[11]++
				cards[i] = 'd'
			case 'A':
				counts[12]++
				cards[i] = 'e'
			default:
				log.Fatalf("invalid card: %v", card)
			}
		}

		for _, count := range counts {
			/*
				if count > 0 && countJ > 0 {
					count += countJ
					countJ = 0
				}
			*/
			switch count {
			case 2:
				strength *= 3
			case 3:
				strength *= 7
			case 4:
				strength *= 11
			case 5:
				strength *= 13
			}
		}

		strength = strengthConv[strength]
		/*
			strengthConv[1] = 1	// high card
			strengthConv[3] = 2	// pair
			strengthConv[9] = 3 // two pairs
			strengthConv[7] = 4 // brelan
			strengthConv[21] = 5 // full
			strengthConv[11] = 6 // carre
			strengthConv[13] = 7 // five

		*/
		switch strength {
		case 1:
			if countJ == 4 {
				strength = 7
			} else if countJ == 3 {
				strength = 6
			} else if countJ == 2 {
				strength = 4
			} else if countJ == 1 {
				strength = 2
			}
		case 2:
			if countJ == 3 {
				strength = 7
			} else if countJ == 2 {
				strength = 6
			} else if countJ == 1 {
				strength = 4
			}
		case 3:
			if countJ == 1 {
				strength = 5
			}
		case 4:
			if countJ == 2 {
				strength = 7
			} else if countJ == 1 {
				strength = 6
			}
		case 6:
			if countJ == 1 {
				strength = 7
			}
		}

		if countJ == 5 {
			strength = 7
		}

		h := Hand{
			original: original,
			cards:    cards,
			bid:      bid,
			strength: strength,
		}

		hands = append(hands, h)
	}

	sort.Slice(hands, func(i, j int) bool {
		if hands[i].strength == hands[j].strength {
			for k := 0; k < 5; k++ {
				if hands[i].cards[k] != hands[j].cards[k] {
					return hands[i].cards[k] < hands[j].cards[k]
				}
			}
			return false
		} else {
			return hands[i].strength < hands[j].strength
		}
	})

	result := 0

	for i, hand := range hands {
		result += (i + 1) * hand.bid
		fmt.Println(string(hand.original))
	}

	return result
}