[模板][字符串] 单哈希

https://oi-wiki.org/string/hash/
https://www.luogu.com.cn/problem/P3370

unsigned long long a[MAXN]; // a 数组记录哈希值


const int prime = 233317;
const unsigned long long MOD = 2123704401301379571;
const unsigned long long base = 131; // 当前进制

unsigned long long Hash(string s){
	int len = s.length();
	
	unsigned long long ans = 0;

	for(int i = 0; i < len; i++){
		(((ans *= base) += (unsigned long long)s[i]) %= MOD) += prime;
	} // 字符串处理需要注意 0 和 <

	return ans;
}



int main(){
	int n ;
	cin>>n;
	string s;

	for(int i = 1; i <= n; i++){
		cin>>s;
		a[i] = Hash(s);
		// while(ext[a[i]]){
		//	  a[i] += 19260817;
		//	  a[i] += Hash(s);
		// }
		ext[a[i]] = 1;
	}

	sort(a+1, a+n+1);

	int ans = 0;
	for(int i = 1; i < n; i++){
		if(a[i] == a[i+1]){
			ans += 1;
		}
	}

	cout<<n - ans;

	return 0;
}