Submission #526080

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
526080	2022-02-13T16:41:22 Z	eric00513	씽크스몰 (kriii3_TT)	C++17	Compilation error	0 ms	0 KB

tt

#include <bits/stdc++.h>
using namespace std;

#define sz(x) (ll)(x).size()
#define all(x) (x).begin(), (x).end()

using ll = unsigned long long;
using base = complex<long double>;

const long double PI = acos(-1);

void fft(vector<base>& a, bool inv) {
	ll n = sz(a);
	for (ll i = 1, j = 0; i < n; i++) {
		ll bit = n >> 1;
		while (j >= bit) j -= bit, bit >>= 1;
		j += bit;
		if (i < j) swap(a[i], a[j]);
	}
	for (ll len = 2; len <= n; len <<= 1) {
		vector<base> w(len / 2);
		for (ll i = 0; i < len / 2; i++) {
			long double ang = 2 * PI * i / len * (inv ? -1 : 1);
			w[i] = base(cos(ang), sin(ang));
		}
		for (ll i = 0; i < n; i += len) {
			for (ll j = 0; j < len / 2; j++) {
				base u = a[i + j], v = a[i + j + len / 2] * w[j];
				a[i + j] = u + v;
				a[i + j + len / 2] = u - v;
			}
		}
	}
	if (inv) for (ll i = 0; i < n; i++) a[i] /= n;
}

vector<ll> multiply(vector<ll>& a, vector<ll>& b) {
	vector<base> fa(all(a)), fb(all(b));
	ll n = sz(fa);
	fft(fa, false); fft(fb, false);
	for (ll i = 0; i < n; i++) fa[i] *= fb[i];
	fft(fa, true);
	vector<ll> ret(n);
	for (ll i = 0; i < n; i++) ret[i] = (ll)(fa[i].real() + (fa[i].real() > 0 ? 0.5 : -0.5));
	return ret;
}

ll main() {
	cin.tie(0);
	ios_base::sync_with_stdio(0);

	ll n, m;
	cin >> n >> m;
	n++, m++;
	ll k = 1;
	while (k < 2 * max(n, m) - 1) k <<= 1;
	vector<ll> a(k), b(k);
	for (ll i = 0; i < n; i++) cin >> a[i];
	for (ll i = 0; i < m; i++) cin >> b[i];

	vector<ll> res = multiply(a, b);
	ll ans = 0;
	for (ll i = 0; i < n + m - 1; i++) ans ^= res[i];
	cout << ans << '\n';
	return 0;
}

Compilation message

tt.cpp:48:1: error: '::main' must return 'int'
   48 | ll main() {
      | ^~