Uestc1063 易位法字符串加密

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<map>
#include<vector>
#include<cmath>
#include<cstdlib>
#include<list>
#include<queue>
#define mm(a,b) memset(a,b,sizeof(a))
#define ACCELERATE (ios::sync_with_stdio(false),cin.tie(0))
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
#define MAXN 0x3f3f3f3f3f3f3f3f
#define PI acos(-1.0)
#define E exp(1.0)
using namespace std;

//#define debug


int main()
{
    #ifdef debug
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    #endif // debug

    char s[25];
    char s1[1025];
    char s2[1025];
    gets(s);
    gets(s1);
    int len=strlen(s);
    int len1=strlen(s1);
    int len2=0;
    for(int i=0;i<len1;i++){
        if(s1[i]==' ') continue;
        s2[len2++]=s1[i];
    }
    int flag;
    if(len2%len) flag=(len2/len+1)*len;
    else flag=len2;
    bool book[25];
    mm(book,0);

    for(int j=0;j<len;j++){
        int mini=MAXN,k;
        for(int i=0;i<len;i++){
            if(!book[i]&&s[i]<mini) mini=s[i],k=i;
        }
        book[k]=1;
        for(int i=k;i<flag;i+=len){

            if(i<len2&&isupper(s2[i])) printf("%c",s2[i]);
            else if(i<len2) printf("%c",towupper(s2[i]));
            else printf("E");
        }
    }
    printf("\n");


    return 0;
}
/*
DCAB
i love china
*/