palindromic cut

#include<bits/stdc++.h>
#define MAX 400005
using namespace std;
int n;
char str[MAX];
int cnt[130]={0};
vector<char> odd,even;
int main()
{
    scanf("%d",&n);
    scanf("%s",&str);
    for(int i=0;i<n;i++) cnt[str[i]]++;
    for(int i='0';i<='z';i++)
    {
        if(cnt[i]<=0) continue;
        if(cnt[i]%2)
        {
            odd.push_back((char)i);
            cnt[i]--;
        }
        while(cnt[i])
        {
            even.push_back(i);
            cnt[i]-=2;
        }
    }

    char ans[MAX];
    if(odd.empty())
    {
        printf("1\n");
        for(int i=0;i<n/2;i++) ans[i]=ans[n-1-i]=even[i];
        ans[n]='\0';
        printf("%s\n",ans);
        return 0;
    }

    while(even.size() % odd.size())
    {
        odd.push_back(even.back());
        odd.push_back(even.back());
        even.pop_back();
    }

    printf("%d\n",odd.size());
    int len=n/odd.size();
    while(!odd.empty())
    {
        ans[len/2]=odd.back();
        odd.pop_back();
        for(int j=0;j<len/2;j++)
        {
            ans[j]=ans[len-1-j]=even.back();
            even.pop_back();
        }
        ans[len]='\0';
        printf("%s ",ans);
    }
}