Function reverseStr

reverse_string_ii_541/solution.go:5–25

(s string, k int)

import "math"

func reverseStr(s string, k int) string {
	r := []rune(s)
	for i := 0; i < len(s); i += 2 * k {
		// get the index to the end of k chars starting at i
		// pick the minimum for the case where the next k
		// characters falls off the end of s.
		j := int(math.Min(float64(i+k-1), float64(len(s)-1)))

		// reverse the string in the range of [i, j]
		s := i
		for s < j {
			hold := r[s]
			r[s] = r[j]
			r[j] = hold
			s++
			j--
		}
	}

	return string(r)
}

// Note: original solution from mock interview.
// I learned how to reverse string in place by using []rune or []byte.