原题链接 - CF

题意就是给 $N$ 个字符串，求本质不同后缀的个数。

看了秒写哈希，一个WA on test 2，就两个，两个还不够就三个，为什么四个还WA on test 2? 求问。

#include <bits/stdc++.h>
using namespace std;
#define ull unsigned long long
set<tuple<ull,ull,ull,ull>> seen;
int main() {
	mt19937_64 rng(time(0));
	const ull Mod1=1e9+7;
	const ull Mod2=1e9+9;
	const ull Mod3=(1ull<<61)-1;
	const ull Mod4=999999999999999989;
	ull base1=rng();
	ull base2=rng();
	ull base3=rng();
	ull base4=rng();
	int n;
	cin>>n;
	for(int i=1;i<=n;i++) {
		string s;
		cin>>s;
		ull h1=0,h2=0,h3=0,h4 = 0;
		for (int j = s.size()-1; j >= 0; j--) {
			ull c = s[j] - 'a';
			h1=(h1*base1+c) % Mod1;
			h2=(h2*base2+c) % Mod2;
			h3=(h3*base3+c) % Mod3;
			h4=(h4*base4+c) % Mod4;
			seen.insert(make_tuple(h1, h2, h3, h4));
		}
	}
	cout << seen.size() << endl;
	return 0;
}