poj 2406 Power Strings（KMP || 暴力）

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题目链接：http://poj.org/problem?id=2406

没想到这道题暴力都能过，而且只有188ms。。。

①kmp（125ms）：

#include<iostream>#include<cstdio>#include<cstring>#include<math.h>#include<algorithm>using namespace std;const int INF=0x3f3f3f3f;const int maxn=1000010;int T,n,m;int next[maxn];char s[maxn];void getNext(char *s){int i=0,j=-1;next[0]=-1;while(s[i]!='\0'){if(j==-1||s[i]==s[j]){i++,j++;next[i]=j;}elsej=next[j];}}int main() {#ifndef ONLINE_JUDGEfreopen("test.in","r",stdin);freopen("test.out","w",stdout);#endifwhile(~scanf("%s",s)){if(!strcmp(s,".")) break;getNext(s);int len=strlen(s);if(len%(len-next[len])==0)printf("%d\n",len/(len-next[len]));elseprintf("1\n");}return 0;}

②暴力（188ms）：

#include<iostream>#include<cstdio>#include<cstring>#include<math.h>#include<algorithm>using namespace std;const int INF=0x3f3f3f3f;const int maxn=1000010;int T,n,m;char s[maxn],subs[maxn];bool ok(char *a,char *b){int len=strlen(a);for(int i=0;i<len;i++)if(a[i]!=b[i])return false;return true;}int main() {#ifndef ONLINE_JUDGEfreopen("test.in","r",stdin);freopen("test.out","w",stdout);#endifwhile(~scanf("%s",s)){if(!strcmp(s,".")) break;int len=strlen(s);for(int i=1;i<=len;i++){if(len%i!=0) continue;bool flag=true;strcpy(subs,s+len-i);for(int j=0;j<=len-i;j+=i){if(!ok(subs,s+j)){flag=false;break;}}if(flag){printf("%d\n",len/i);break;}}}return 0;}

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