双重Hash

//双重Hash 可保证不重复 
//空间较大 时间较慢 不易被卡
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#define MOD1 233333339
#define MOD2 233333393
#define MOD3 233333939
#define base 233
#define ull unsigned long long
using namespace std;
ull n,ans=1,len;
char s[10001];
struct uio{
    ull a,b;
}hash[10001];
bool cmp(uio x,uio y)
{
    return x.a<y.a;
}
ull hash1(char s[])
{
    ull ans=0;
    for(ull i=0;i<len;i++)
        ans=(ans*base+(ull)s[i])%MOD1;
    return ans;
}
ull hash2(char s[])
{
    ull ans=0;
    for(ull i=0;i<len;i++)
        ans=(ans*base+(ull)s[i])%MOD2;
    return ans;
}
int main()
{
    scanf("%llu",&n);
    for(ull i=1;i<=n;i++)
    {
        scanf("%s",s);
        len=strlen(s);
        hash[i].a=hash1(s);
        hash[i].b=hash2(s);
    }
    sort(hash+1,hash+n+1,cmp);
    for(ull i=2;i<=n;i++)
        if(hash[i].a!=hash[i-1].a&&hash[i].b!=hash[i-1].b)
            ans++;
    printf("%llu",ans);
     return 0;
}
原文地址:https://www.cnblogs.com/water-radish/p/9280659.html