aoc2023/day-5/one.go

package main

import (
	"math"
)

var seeds = []int{}

// next recursively calculates each destination for each set of data in dataMap
func next(i int, datapoint int) int {
	if i == len(identifiers) {
		return datapoint
	}

	dest := 0
	for _, data := range dataMap[identifiers[i]] {
		if datapoint >= data.source && datapoint <= data.source+data.offset {
			dest = data.dest + (datapoint - data.source)
			break
		}
	}
	if dest == 0 {
		dest = datapoint
	}
	return next(i+1, dest)
}

// one returns the lowest location for any seed in seeds
func one(lines []string) (int, error) {
	parseLines(lines)

	lowest := math.MaxInt
	for _, seed := range seeds {
		location := next(0, seed)
		if location < lowest {
			lowest = location
		}
	}

	return lowest, nil
}