优化！优化！

读入的字符串包含空格！

数据量较大，vector string都会降低效率

简直优化哭了要( ▼-▼ )

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <string>
#include <iostream>
#include <vector>
using namespace std;

const int maxn = 1005;

int read(char s[]) {
    char c;
    int i = 0;
    c = getchar();
    if(c == EOF)
        return 0;
    while(c != '\n'&&c != EOF) {
        s[i++] = c;
        c = getchar();
    }
    s[i] = '\0';
    return i;
}

int main() {
    //std::ios::sync_with_stdio(false);
    char s[maxn];
    while(read(s)) {
        int len = (int)strlen(s);
        for(int i = len / 2 + 1;i > 0;i--) {
            char temp[maxn];
            strcpy(temp,s);
            int v[maxn];
            int it = 0;
            for(int j = i;j <= len;j += i)
                v[it++] = j;

            for(int j = 0;j < it;j++) {
                int t = (i % 2 ? j + 1 : j - 1);
                t = t == -1 ? it - 1 : t == it ? t == 0 : t;
                s[v[j] - 1] = temp[v[t] - 1];
            }
            //cout << " " << s << endl;
            //v.erase(v.begin(),v.end());
        }
        cout << s << endl;
    }
    return 0;
}