golang力扣leetcode 6.Z字形变换

package main
func convert(s string, numRows int) string {
  if numRows == 1 || numRows >= len(s) {//只有一行，或者行数超过字符串长度
    return s
  }
  res := make([][]byte, numRows)
  i, flag := 0, -1
  for _, v := range []byte(s) {
    res[i] = append(res[i], v)
    if i == 0 || i == numRows-1 {
      flag = -flag
    }
    i += flag
  }
  result := ""
  for _, v := range res {
    result += string(v)
  }
  return result
}