二进制哈希法；

#include <iostream>#include <string>using namespace std;#define ONE32 0x00000001unsigned int flag[100]={0};// 字符串标记数组int pos=0;int main(){while(true){string str;cin>>str;unsigned int sum=0;//计算哈希值for(string::size_type i=0;i<str.length();++i){sum=sum|ONE32<<(((int)str[i]-97));}//查找是否已出现bool ifExist=false;for(int i=0;i<100;++i){if(flag[i]==sum){cout<<"已存在"<<endl;ifExist=true;break;}}if(!ifExist){flag[pos++]=sum;}}system("pause");return 0;}

 

二进制判断有无重复字符串.

 

abc

cba 算同样的重复字符串.