【CF1029A】Many Equal Substrings（模拟）

题意：给定一个长度为n的串s，要求构造一个长度最小的使s出现了k次的串，可以重叠

n<=50,k<=50

思路：计算一下前后缀相同长度

 #include<cstdio>
 #include<cstring>
 #include<string>
 #include<cmath>
 #include<iostream>
 #include<algorithm>
 #include<map>
 #include<set>
 #include<queue>
 #include<vector>
 using namespace std;
 typedef long long ll;
 typedef unsigned int uint;
 typedef unsigned long long ull;
 typedef pair<int,int> PII;
 typedef vector<int> VI;
 #define fi first
 #define se second
 #define MP make_pair
 #define N   5100000
 #define MOD 1e9+7
 #define eps 1e-8
 #define pi acos(-1)

 char ch[];

 int read()
 {
    int v=,f=;
    char c=getchar();
    while(c<||<c) {if(c=='-') f=-; c=getchar();}
    while(<=c&&c<=) v=(v<<)+v+v+c-,c=getchar();
    return v*f;
 }

 void swap(int &x,int &y)
 {
     int t=x;x=y;y=t;
 }

 int main()
 {
     //freopen("1.in","r",stdin);
     //freopen("1.out","w",stdout);
     int n,k1;
     scanf("%d%d",&n,&k1);
     scanf("%s",ch+);
     int st=;
     int flag;
     for(int i=n-;i>=;i--)
     {
          flag=;
         int j=;
         int k=n-i+;
         while(k<=n&&j<=i)
         {
             if(ch[j]!=ch[k]){flag=; break;}
             j++; k++;
         }
         if(flag){st=j-; break;}
     }

 //    printf("%d\n",st);
     for(int i=;i<=st;i++) printf("%c",ch[i]);
     for(int i=;i<=k1;i++)
      for(int j=st+;j<=n;j++) printf("%c",ch[j]); 

     return ;
 }