题目
Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. 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.
Example:
Input: s = "abcdefg", k = 2
Output: "bacdfeg"
Restrictions:
- The string consists of lower English letters only.
- Length of the given string and k will in the range [1, 10000]
解题思路
找到需要翻转的子串翻转即可
代码
func reverseRune(r []rune, start, end int) {
for ; start < end; {
r[start], r[end] = r[end], r[start]
start++
end--
}
}
func reverseStr(s string, k int) string {
sRune := []rune(s)
len1 := len(s)
for i := 0; i < len1; i += k * 2 {
end := i + k - 1
if end > len1 - 1{
end = len1 - 1
}
reverseRune(sRune, i, end)
}
ret := string(sRune)
return ret
}
