class Solution {
  public String convert(String s, int numRows) {
    if (numRows == 1) {
      return s;
    }

    char[] result = new char[s.length()];

    int term = (numRows - 1) * 2;

    int index = 0;

    for (int i = 0; i < numRows; i++) {
      int tempTerm = i * 2;
      for (int j = i; j < s.length(); j = j + tempTerm) {
        result[index] = s.charAt(j);
        index++;
        tempTerm = term - tempTerm == 0 ? term : term - tempTerm;
      }
    }
    return String.valueOf(result);
  }
}