LeetCode/go/construct-string-with-repeat-limit.go

package main

import (
	"cmp"

	pq "github.com/emirpasic/gods/v2/queues/priorityqueue"
)

func repeatLimitedString(s string, repeatLimit int) string {
	charReversed := func(a, b rune) int {
		return cmp.Compare(b, a)
	}

	getFreqs := func() map[rune]int {
		f := make(map[rune]int)
		for _, c := range s {
			count, found := f[c]

			if found {
				count++
			} else {
				count = 1
			}

			f[c] = count
		}

		return f
	}
	freqs := getFreqs()

	q := pq.NewWith(charReversed)
	for k, _ := range freqs {
		q.Enqueue(k)
	}

	result := []rune{}
	for c, ok := q.Dequeue(); ok; c, ok = q.Dequeue() {
		k := min(freqs[c], repeatLimit)
		for i := 0; i < k; i++ {
			result = append(result, c)
		}
		freqs[c] -= k

		if freqs[c] > 0 {
			nextC, ok := q.Dequeue()
			if !ok {
				break
			}

			result = append(result, nextC)
			freqs[nextC]--

			if freqs[nextC] > 0 {
				q.Enqueue(nextC)
			}
			q.Enqueue(c)
		}
	}

	return string(result)
}