leetcode --344. Reverse String

Write a function that takes a string as input and returns the string reversed.

Example:
Given s = "hello", return "olleh".

class Solution {
public:
    string reverseString(string s) {
            int i = 0 ;
            int j = s.size()-1;
            while(i<j)
            {
                char temp = s[i];
                s[i++] = s[j];
                s[j--] = temp;;
 
            }
            return s;
    }
};

 

class Solution{
public:
    string reverseString(string s){
        int i , j , n;
        n = strlen(s);
        char* tmp = (char*)malloc(sizeof(char)*(n+1));
        for(i=n,j=0;i>0;i--,j++)
           tmp[j] = s[i-1];
        tmp[n] = '\0';
        return tmp ;
    }
};