LeetCode/go/strange-printer.go

package main

import "strings"

func strangePrinter(s string) int {
	mergeConsecutive := func() string {
		withoutConsecutive := strings.Builder{}

		for i := 0; i < len(s); {
			c := s[i]
			withoutConsecutive.WriteByte(c)

			for i < len(s) && s[i] == c {
				i++
			}
		}

		return withoutConsecutive.String()
	}

	compute := func(s string, dp [][]int, length int) {
		for l := 0; l+length-1 < len(s); l++ {
			r := l + length - 1

			dp[l][r] = length

			for mid := 0; mid < length-1; mid++ {
				turns := dp[l][l+mid] + dp[l+mid+1][r]

				if s[l+mid] == s[r] {
					turns--
				}

				dp[l][r] = min(
					dp[l][r],
					turns,
				)
			}
		}
	}

	s = mergeConsecutive()
	n := len(s)

	// Make a DP table
	dp := make([][]int, n)
	for i := range n {
		dp[i] = make([]int, n)
		dp[i][i] = 1
	}

	for length := 2; length <= n; length++ {
		compute(s, dp, length)
	}

	return dp[0][n-1]
}