哈希和双哈希

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哈希自然溢出

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<set>
#define LL long long
#define maxn 10005
#define S 131
using namespace std;

int n;
char s[maxn];
set<LL>st;

int main()
{
	scanf("%d",&n);	
	for(;n--;)
	{
		scanf("%s",s);
		int len = strlen(s);LL val = 0;
		for(int i=0;i<len;i++) val = val * S + s[i];
		st.insert(val);
	}
	printf("%d\n",st.size());
}

双哈希

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<set>
#define LL long long
#define maxn 10005
#define S 131
#define mod1 998244353
#define mod2 1000000007
using namespace std;

int n;
char s[maxn];
set<pair<int,int> >st;

int main()
{
	scanf("%d",&n);	
	for(;n--;)
	{
		scanf("%s",s);
		int len = strlen(s);LL val1 = 0,val2 = 0;
		for(int i=0;i<len;i++) 
			val1 = (1ll * val1 * S + s[i]) % mod1,
			val2 = (1ll * val2 * S + s[i]) % mod2;
		st.insert(make_pair(val1,val2));
	}
	printf("%d\n",st.size());
}