字符串－leetcode 541. Reverse String II

原题链接：Reverse String

题解：

public class Solution {
    public String reverseStr(String s, int k) {
        /*
            Time Complexity:O(N)
            Space Complexity:O(N)
        */
        char[] res=s.toCharArray();
        for(int i=0;i<res.length;i+=2*k){
            for(int x=i,y=Math.min(i+k-1,res.length-1);x<y;x++,y--){
                char temp=res[x];
                res[x]=res[y];
                res[y]=temp;
            }
        }
        return new String(res);
    }
}