字符串逆序-双字符串解法

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define size 5
void reverseString(char* s,char* s1)
{
    int i,j;
    int length = strlen(s);
    for (i = 0,j = length-1;i < length;i++,j--)
    {
        s1[i] = s[j];
    }
}

int main()
{

    char *s;
    char *s1;
    s = malloc(size * sizeof(char));
    s1 = malloc(size * sizeof(char));
    scanf("%s",s);
    printf("O:%s\n",s);
    reverseString(s,s1);
    printf("R:%s\n",s1);
    free(s);
    free(s1);
}

复杂度分析：双字符串解法的时间复杂度为O(n);空间复杂度为O(2n);