LeetCode-探索-初级-字符串-反转字符串-java

编写一个函数，其作用是将输入的字符串反转过来。

示例 1:

[code]输入: "hello"
输出: "olleh"

示例 2:

[code]输入: "A man, a plan, a canal: Panama"
输出: "amanaP :lanac a ,nalp a ,nam A"

方法可以有很多，任君选择，总体思路就是反转数组即可：

1.反转方式

2.循环的"/2"可以利用">>1"替代d

后面是我写的几种方法：

[code]public String reverseString(String s) {
char[] chars = s.toCharArray();
int limit = chars.length / 2;
int symmetryI = 0;
for (int i = 0 ; i < limit ; i ++) {
symmetryI = chars.length - 1 - i;
chars[i] = (char) (chars[i] ^ chars[symmetryI]);
chars[symmetryI] = (char)(chars[i] ^ chars[symmetryI]);
chars[i] = (char)(chars[i] ^ chars[symmetryI]);
}
return new String(chars);
}

public String reverseString0(String s) {
char[] chars = s.toCharArray();
int limit = chars.length >> 1;
char temp = 0;
int symmetryI = 0;
for (int i = 0 ; i < limit ; i ++) {
symmetryI = chars.length - 1 - i;
temp = chars[i];
chars[i] = chars[symmetryI];
chars[symmetryI] = temp;
}
return new String(chars);
}

public String reverseString1(String s) {
char[] chars = s.toCharArray();
char[] target = new char[chars.length];
for (int i = chars.length - 1 ; i >= 0 ; i --)
target[chars.length - 1 - i] = chars[i];
return new String(target);
}

public String reverseString2(String s) {
return new StringBuilder(s).reverse().toString();
}

利用位运算来进行 /2 或者两个数交换的技巧在之前应该说过，不在赘述