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
1 #include<cstdio> 2 #include<cstring> 3 #include<string> 4 #include<cmath> 5 #include<iostream> 6 #include<algorithm> 7 #include<map> 8 #include<set> 9 #include<queue> 10 #include<vector> 11 using namespace std; 12 typedef long long ll; 13 typedef unsigned int uint; 14 typedef unsigned long long ull; 15 typedef pair<int,int> PII; 16 typedef vector<int> VI; 17 #define fi first 18 #define se second 19 #define MP make_pair 20 #define N 5100000 21 #define MOD 1e9+7 22 #define eps 1e-8 23 #define pi acos(-1) 24 25 char ch[100]; 26 27 28 29 int read() 30 { 31 int v=0,f=1; 32 char c=getchar(); 33 while(c<48||57<c) {if(c=='-') f=-1; c=getchar();} 34 while(48<=c&&c<=57) v=(v<<3)+v+v+c-48,c=getchar(); 35 return v*f; 36 } 37 38 void swap(int &x,int &y) 39 { 40 int t=x;x=y;y=t; 41 } 42 43 44 45 int main() 46 { 47 //freopen("1.in","r",stdin); 48 //freopen("1.out","w",stdout); 49 int n,k1; 50 scanf("%d%d",&n,&k1); 51 scanf("%s",ch+1); 52 int st=0; 53 int flag; 54 for(int i=n-1;i>=1;i--) 55 { 56 flag=1; 57 int j=1; 58 int k=n-i+1; 59 while(k<=n&&j<=i) 60 { 61 if(ch[j]!=ch[k]){flag=0; break;} 62 j++; k++; 63 } 64 if(flag){st=j-1; break;} 65 } 66 67 // printf("%d ",st); 68 for(int i=1;i<=st;i++) printf("%c",ch[i]); 69 for(int i=1;i<=k1;i++) 70 for(int j=st+1;j<=n;j++) printf("%c",ch[j]); 71 72 return 0; 73 }