Write a function that reverses a string. The input string is given as an array of characters s.
You must do this by modifying the input array in-place with O(1) extra memory.
Example 1:
Input: s = [“h”,“e”,“l”,“l”,“o”]
Output: [“o”,“l”,“l”,“e”,“h”]
Example 2:
Input: s = [“H”,“a”,“n”,“n”,“a”,“h”]
Output: [“h”,“a”,“n”,“n”,“a”,“H”]
把字符串s逆序排列。
思路:
位置0和n-1交换,1和n-2交换。。
知道左右两指针相遇。
public void reverseString(char[] s) {
int left = 0;
int right = s.length - 1;
while(left < right) {
char tmp = s[left];
s[left] = s[right];
s[right] = tmp;
left ++;
right --;
}
}