算法1

(双指针)

C++ 代码

class Solution {
public:
    void reverseString(vector<char>& s) {
        int i=0,j=s.size()-1;
        int n=s.size();
        for(int i=0;i<n/2;i++,j--){
            swap(s[i],s[j]);
        }
    }
};

算法2

(递归)

C++ 代码

class Solution {
public:
    void reverseString(vector<char>& s) {
        if(s.size()==0) return;
        reverse(s,0,s.size()-1);
    }
    void reverse(vector<char>&s,int left,int right){
        if(left>=right) return;
        reverse(s,left+1,right-1);
        swap(s[left],s[right]);
    }
};