You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: d.go
    path of file: ./repos/codeforces-go/leetcode/weekly/368/d
    
    the code of the file until where you have to start completion: package main

// https://space.bilibili.com/206214
// 预处理每个数的不包括自己的因子，时间复杂度 O(mx*log(mx))
const mx = 200

var divisors [mx + 1][]int

func init() {
	for i := 1; i <= mx; i++ {
		for j := i * 2; j <= mx; j += i {
			divisors[j] = appen
    
func minimumChanges(s string, k int) (ans int) {
	n := len(s)
	modify := make([][]int, n-1)
	for l := range modify {
		modify[l] = make([]int, n)
		for r := l + 1; r < n; r++ { // 半回文串长度至少为 2
			modify[l][r] = calc(s[l : r+1])
		}
	}

	f := modify[0]
	for i := 1; i < k; i++ {
		for j := n - 1 - (k-1-i)*2; j > i*2; j-- {
			f[j] = n
			for L := i * 2; L < j; L++ {
				f[j] = min(f[j], f[L-1]+modify[L][j])
			}
		}
	}
	return f[n-1]
}