LeetCode 541. Reverse String II

question:

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]

 

try:

class Solution {
    public String reverseStr(String s, int k) {
        char[] charArray=s.toCharArray();
        int length=charArray.length;
        char[] result=new char[length];
        
        for(int i=0;i<length;i++){
            if((i/k)%2==0){
                if(length<((i/k)*k+k)){
                    result[length-1-i%k]=charArray[i];
                    //continue;
                }else{
                    result[(i/k)*k+k-1-i%k]=charArray[i];     
                }

                
            }else {
                result[i]=charArray[i];
            }
                
        }
        return new String(result);
    }
}

 result: 22.58%

 

conclusion:

dm