package q6

import "strings"

func convert(s string, numRows int) string {
	loopLen := numRows + max(0, numRows-2)
	rows := make([][]byte, numRows)
	for i := range numRows {
		rows[i] = make([]byte, 0, (len(s)/loopLen+1)*2)
	}

	for i := range len(s) {
		row := i % loopLen
		if row >= numRows {
			row = numRows - row%numRows - 2
		}
		rows[row] = append(rows[row], s[i])
	}

	b := strings.Builder{}
	for i := range rows {
		_, _ = b.Write(rows[i])
	}
	return b.String()
}

var _ = convert