https://www.cnblogs.com/widsom/p/8058358.htm （详细解释）
//#include<bits/stdc++.h> #include<vector> #include<cstdio> #include<cstring> #include<iostream> #define ull unsigned long long using namespace std; const int maxn=1e6+10; char a[maxn]; ull b[maxn]; ull c[maxn]; int main() { b[0]=1; ull d=33; for(int i=1;i<=maxn;i++) b[i]=b[i-1]*d; while(1) { scanf("%s",a+1); int n=strlen(a+1); if(n==1 && a[1]=='.') break; for(int i=1;i<=n;i++) c[i]=c[i-1]*d+(a[i]-'a'+1); vector<int> vs; for(int i=1;i<=n;i++) { if(n%i==0) vs.push_back(i); } int ans=1; for(int i=0;i<vs.size();i++) { int flag=1; for(int j=2*vs[i];j<=n;j+=vs[i]) { ull x=c[j]-c[j-vs[i]]*b[vs[i]]; if(x!=c[vs[i]]) {flag=0; } } if(flag) {ans=n/vs[i]; break; } } printf("%d\n",ans); } }
//#include<bits/stdc++.h> #include<vector> #include<cstdio> #include<cstring> #include<iostream> #define ull unsigned long long using namespace std; const int maxn=1e6+10; char ss[maxn]; int nt[maxn]; int KMP() { int l=strlen(ss); nt[0]=-1; for (int i = 1; i < l; ++i) { int j = nt[i-1]; while(ss[j+1] != ss[i] && j >= 0) j = nt[j]; if(ss[j+1] == ss[i]) nt[i] = j+1; else nt[i] = -1; } for(int i=0;i<l;i++) { cout<<nt[i]<<endl; } int k=l-(nt[l-1]+1); if(l%k==0) return l/k; else return 1; } int main() { while(1) { scanf("%s",ss); int n=strlen(ss); if(n==1 &&ss[0]=='.') break; printf("%d\n",KMP()); } }