動機
就reverse
Problem
Write a function that reverses a string. The input string is given as an array of characters s
.
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]
Constraints:
1 <= s.length <= 105
s[i]
is a printable ascii character.
Follow up: Do not allocate extra space for another array. You must do this by modifying the input array in-place with O(1)
extra memory.
Sol
class Solution:
def reverseString(self, s: List[str]) -> None:
i,j = 0, len(s)-1
while i < j:
s[i],s[j] = s[j],s[i]
i,j = i+1,j-1