leetcode 344 Reverse String (in java)

简单的字符串反转

方法一

public String reverseString(String s) {    int len = s.length();    StringBuilder res = new StringBuilder(len);    for(int i = len - 1; i >= 0; i--){        res.append(s.charAt(i));    }    return res.toString();}

在leetcode中运行，Runtime: 5 ms

方法二

public String reverseString(String s) {    if(s == null || s.length() == 0){        return s;    }    char[] sArr = s.toCharArray();    int start = 0;    int end = s.length() - 1;    reverseStr(sArr, start, end);    return new String(sArr);}public char[] reverseStr(char[] StrArr, int start, int end){    if(StrArr == null){        return null;    }    while(start < end){        char temp = StrArr[start];        StrArr[start++] = StrArr[end];        StrArr[end--] = temp;    }    return StrArr;}

在leetcode中运行，Runtime: 3 ms