hdu4731 Minimum palindrome (找规律)

这道题找下规律，3个字母或者以上的时候就用abcabcabc....循环即可。

一个字母时，就是aaaaa.....;

当只有2个字母时！
s[1][]=a";

s[2][]="ab";

s[3][]="aab";

s[4][]="aabb";

s[5][]="aaaba";

s[6][]=""aaabab";

s[7][]=""aaababb";

s[8][]=""aaababbb";

s[9][]=""aaaababba";

下面是循环的字符串！！！！
add[1][]="a";

add[2][]="aa";

add[3][]="aaa";

add[4][]="aaaa";

add[5][]="aabab";

add[6][]="aababb";

打表程序！！！

 下面是打表程序！！！！

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
 #include<vector>
 #include<time.h>
 #include<algorithm>
 using namespace std;
 int dp[];
 int pan(int s[],int n)
 {
     int i,j,k;
     int ans=;
     for(i=;i<=n;i++)
     {
         int flag=;
         for(j=;j<=n-i+;j++)
         {
             int x,y;
             x=j;y=i+j-;
             while(x<=y)
             {
                 if(s[x]!=s[y])break;
                 x++;y--;
             }
             if(x>y)flag=;
         }
         if(flag)ans=i;
     }
     return ans;
 }
 int main()
 {
     int i,j;
     int n;
     int s[];
     while(~scanf("%d",&n))
     {
         int ans,L;
         L=;
         for(i=(<<n)-;i>=;i--)
         {
             int tmp=i;
             for(j=n;j>=;j--)
             {
                 s[j]=tmp%;
                 tmp/=;
             }
             int tt=pan(s,n);
             if(tt<=L)L=tt,ans=i;
         }
             int tmp=ans;
             for(j=n;j>=;j--)
             {
                 s[j]=tmp%;
                 tmp/=;
             }
             for(i=;i<=n;i++)
             if(s[i])printf("b");
             else    printf("a");
             printf("\n");
     }
 }
 /*
 2
 ab
 3
 aab
 4
 aabb
 5
 aaaba
 6
 aaabab
 7
 aaababb
 8
 aaababbb
 9
 aaaababba
 10
 aaaababba  a
 11
 aaaababba  aa
 12
 aaaababba  aaa
 13
 aaaababba  abab
 14
 aaaababba  ababb
 15
 aaaababba  ababba
 16
 aaaababba  ababba  a
 17
 aaaababba  ababba  aa
 18
 aaaababba  ababba  aaa
 19
 aaaababba  ababba  abab
 20
 aaaababba  ababba  ababb
 21
 aaaababba  ababba  ababba
 */

正解！！！

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
 #include<vector>
 #include<time.h>
 #include<algorithm>
 using namespace std;
 int cnt[];
 char s[][],add[][];
 void pre()
 {
     s[][]='a';s[][]=;
     s[][]='a';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='b';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='a';s[][]='b';s[][]='a';s[][]=;
     s[][]='a';s[][]='a';s[][]='a';s[][]='b';s[][]='a';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='a';s[][]='b';s[][]='a';s[][]='b';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='a';s[][]='b';s[][]='a';s[][]='b';s[][]='b';s[][]='b';s[][]=;
     s[][]='a';s[][]='a';s[][]='a';s[][]='a';s[][]='b';s[][]='a';s[][]='b';s[][]='b';s[][]='a';s[][]=;

     add[][]='a';add[][]=;
     add[][]='a';add[][]='a';add[][]=;
     add[][]='a';add[][]='a';add[][]='a';add[][]=;
     add[][]='a';add[][]='b';add[][]='a';add[][]='b';add[][]=;
     add[][]='a';add[][]='b';add[][]='a';add[][]='b';add[][]='b';add[][]=;
     add[][]='a';add[][]='b';add[][]='a';add[][]='b';add[][]='b';add[][]='a';add[][]=;
 }
 int main()
 {
     pre();
     int i,j;
     int T;
     int ca=;
     scanf("%d",&T);
     while(T--)
     {
         ca++;
         int m,n;
         scanf("%d%d",&m,&n);
         printf("Case #%d: ",ca);
         if(m==)
         {
             for(i=;i<=n;i++)
                 printf("a");
             printf("\n");
             continue;
         }
         if(m==)
         {
             if(n<=)printf("%s",s[n]);
             else
             {
                 printf("%s",s[]);
                 n=n-;
                 for(i=;i<=n/;i++)
                 {
                     printf("%s",add[]);
                 }
                 if(n%)printf("%s",add[n%]);
             }
             printf("\n");
             continue;
         }
         char tmp='a';
         for(i=;i<=n;i++)
         {
             printf("%c",tmp);
             if(i%==)tmp='a';
             else tmp++;
         }
         printf("\n");
     }
 }