Function reverseStrOrig

reverse_string_ii_541/solution.go:32–81

Note: original solution from mock interview. I learned how to reverse string in place by using []rune or []byte. Having to reverse by string concatenation make this problem tough. Also, the problem description was vague in cases with characters remaining to sort.

(s string, k int)

// Also, the problem description was vague in cases with characters
// remaining to sort.
func reverseStrOrig(s string, k int) string {
	if len(s) < k {
		return s
	}

	i := 0
	for i+k < len(s) {
		end := i + k
		j := end - 1
		revStr := ""
		for j >= i {
			revStr += string(s[j])
			j--
		}

		s = s[0:i] + revStr + s[end:]
		i = i + (2 * k)

		// if there are less than k characters left, reverse all of them
		charsLeft := len(s) - end
		if charsLeft < k {
			// reverse all of them
			e := len(s) - 1
			revStr := ""
			for e >= end {
				revStr += string(s[e])
				e--
			}

			s = s[0:end] + revStr
		}

		// if there are less than 2k but greater than or equal to k characters,
		// then reverse the first k characters and left the other as original
		if charsLeft < 2*k && charsLeft > k {
			// reverse the first k characters
			h := end + k
			e := h - 1
			revStr := ""
			for e >= end {
				revStr += string(s[e])
				e--
			}

			s = s[0:end] + revStr + s[h:]
		}
	}

	return s
}