Submission #557726

#	Time	Username	Problem	Language	Result	Execution time	Memory
557726		hhhhaura	Boat (APIO16_boat)	C++14	100 / 100	1696 ms	18252 KiB

boat

#define wiwihorz
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse")
#pragma loop-opt(on)
#define rep(i, a, b) for(int i = a; i <= b; i ++)
#define rrep(i, a, b) for(int i = b; i >= a; i --)
#define all(x) x.begin(), x.end()
#define ceil(a, b) ((a + b - 1) / (b))
#define int long long int
#define lld long double
#define pii pair<int, int>
#define random mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count())
#define INF 1000000000000000000
#define MOD 1000000007
#define eps (1e-9)
using namespace std;
#ifdef wiwihorz
#define print(a...)cerr<<"Line "<<__LINE__<<":",kout("["+string(#a)+"] = ", a)
void vprint(auto L,auto R){while(L<R)cerr<<*L<<" \n"[next(L) == R], ++L; }
void kout() { cerr << endl; }
template<class T1,class ... T2>void kout(T1 a,T2 ... e){cerr<<a<<" ",kout(e...);}
#else
#define print(...) 0
#define vprint(...) 0
#endif
#define x first
#define y second
namespace solver {
	int n, tot;
	vector<pii> seg;
	vector<int> v, fac, inv;
	vector<vector<int>> dp, pre, P, cal, C;
	int pow_(int a, int times) {
		int ans = 1;
		for(; times > 0; times >>= 1, a = a * a % MOD) {
			if(times & 1) ans = ans * a % MOD;
		}
		return ans;
	}
	void init_(int _n) {
		n = _n;
		v.clear();
		seg.assign(n + 1, {0, 0});
		dp.assign(n + 1, vector<int>(n * 2 + 1, 0));
		pre.assign(n * 2 + 1, vector<int>(n + 1, 0));
		P.assign(n * 2 + 1, vector<int>(n + 1, 0));
		C.assign(n + 1, vector<int>(n + 1, 0));
		cal.assign(n * 2 + 1, vector<int>(n + 1, 0));
		fac.assign(n + 1, 1);
		inv.assign(n + 1, 1);
		rep(i, 1, n) fac[i] = fac[i - 1] * i % MOD;
		inv[n] = pow_(fac[n], MOD - 2);
		rrep(i, 1, n - 1) inv[i] = inv[i + 1] * (i + 1) % MOD;
		rep(i, 0, n) rep(j, 0, i) {
			C[i][j] = fac[i] * inv[j] % MOD * inv[i - j] % MOD;
		}
	}
 
	void solve() {
		sort(all(v));
		v.resize(unique(all(v)) - v.begin());
		tot = v.size() - 1;
		rep(i, 1, n) {
			int L = seg[i].x, R = seg[i].y;
			L = lower_bound(all(v), L) - v.begin() + 1;
			R = lower_bound(all(v), R + 1) - v.begin();
			seg[i] = {L, R};
		}
		int l = 0, cur = 1;
		rep(i, 1, tot) {
			int len = v[i] - v[i - 1];
			rep(j, 1, min(n, len)) {
				int L = 1, R = 1;
				rep(k, 0, j - 1) L = L * (len - k) % MOD;
				rep(k, 1, j) R = R * k % MOD;
				P[i][j] = L * pow_(R, MOD - 2) % MOD;
			}
		}
		rep(i, 1, tot) {
			vector<int> p = P[i];
			rep(j, 1, n) {
				rep(k, 1, j) cal[i][j] += p[k] * C[j - 1][k - 1] % MOD;
				cal[i][j] %= MOD;
			}
		}
		dp[0][0] = 1;
		rep(i, 0, tot) pre[i][0] = 1;
		rep(i, 1, n) {
			int L = seg[i].x, R = seg[i].y;
			rep(j, 1, tot) if(L <= j && j <= R) {
				int cnt = 0;
				rrep(k, 0, i - 1) {
					cnt += (seg[k + 1].x <= j && seg[k + 1].y >= j);
					dp[i][j] += pre[j - 1][k] * cal[j][cnt] % MOD;
				}
				dp[i][j] %= MOD;
			}
			rep(j, 1, tot) pre[j][i] = (pre[j - 1][i] + dp[i][j]) % MOD;
		}
		int ans = 0;
		rep(i, 1, n) ans = (ans + pre[tot][i]) % MOD;
		cout << ans << "\n";
	}
	
};
using namespace solver;
signed main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int n; cin >> n;
	init_(n);
	rep(i, 1, n) {
		cin >> seg[i].x >> seg[i].y;
		v.push_back(seg[i].x);
		v.push_back(seg[i].y + 1);
	}
	solve();
	return 0;
}

Compilation message (stderr)

boat.cpp:5: warning: ignoring '#pragma loop ' [-Wunknown-pragmas]
    5 | #pragma loop-opt(on)
      | 
boat.cpp:20:13: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   20 | void vprint(auto L,auto R){while(L<R)cerr<<*L<<" \n"[next(L) == R], ++L; }
      |             ^~~~
boat.cpp:20:20: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   20 | void vprint(auto L,auto R){while(L<R)cerr<<*L<<" \n"[next(L) == R], ++L; }
      |                    ^~~~
boat.cpp: In function 'void solver::solve()':
boat.cpp:70:7: warning: unused variable 'l' [-Wunused-variable]
   70 |   int l = 0, cur = 1;
      |       ^
boat.cpp:70:14: warning: unused variable 'cur' [-Wunused-variable]
   70 |   int l = 0, cur = 1;
      |              ^~~

• Subtask 1: 9 / 9
• Subtask 2: 22 / 22
• Subtask 3: 27 / 27
• Subtask 4: 42 / 42