周期串(Periodic Strings,UVa455)

#include<iostream> #include<string> using namespace std; bool periodic(string s,string sub){ int lensub = sub.length(); int lens = s.length(); for(int i = 0;i < s.length();i++){ if(s[i] != sub[i % lensub]) return false; } return true; } int main(){ string s; string sub; cin>>s; int i; for(i = 1;i < s.length();i++){ sub = s.substr(0,i); if(periodic(s,sub) == true){ cout<<sub<<endl; break; } } return 0; }