Submission #705055

#	Time	Username	Problem	Language	Result	Execution time	Memory
705055		600Mihnea	Boat (APIO16_boat)	C++17	0 / 100	2041 ms	6712 KiB

boat

#include <cmath>
#include <functional>
#include <fstream>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <list>
#include <time.h>
#include <math.h>
#include <random>
#include <deque>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <cassert>
#include <bitset>
#include <sstream>
#include <chrono>
#include <cstring>
#include <numeric>

using namespace std;

typedef long long ll;
const int M = (int)1e9 + 7;
const int FACTN = 300000 + 7;

int add(int a, int b) {
	a += b;
	if (a >= M) return a - M;
	if (a < 0) return a + M;
	return a;
}

int mul(int a, int b) {
	return a * (ll)b % M;
}

int add(int a, int b, int c) {
	return add(add(a, b), c);
}

int mul(int a, int b, int c) {
	return mul(mul(a, b), c);
}

int add(int a, int b, int c, int d) {
	return add(add(a, b, c), d);
}

int mul(int a, int b, int c, int d) {
	return mul(mul(a, b, c), d);
}

int add(int a, int b, int c, int d, int e) {
	return add(add(a, b, c, d), e);
}

int mul(int a, int b, int c, int d, int e) {
	return mul(mul(a, b, c, d), e);
}

int add(int a, int b, int c, int d, int e, int f) {
	return add(add(a, b, c, d, e), f);
}

int mul(int a, int b, int c, int d, int e, int f) {
	return mul(mul(a, b, c, d, e), f);
}

int add(int a, int b, int c, int d, int e, int f, int g) {
	return add(add(a, b, c, d, e, f), g);
}

int mul(int a, int b, int c, int d, int e, int f, int g) {
	return mul(mul(a, b, c, d, e, f), g);
}

int add(int a, int b, int c, int d, int e, int f, int g, int h) {
	return add(add(a, b, c, d, e, f, g), h);
}

int mul(int a, int b, int c, int d, int e, int f, int g, int h) {
	return mul(mul(a, b, c, d, e, f, g), h);
}

int pw(int a, int b) {
	int r = 1;
	while (b) {
		if (b & 1) r = mul(r, a);
		a = mul(a, a);
		b /= 2;
	}
	return r;
}

int dv(int a, int b) {
	return mul(a, pw(b, M - 2));
}

void addup(int& a, int b) {
	a = add(a, b);
}

void mulup(int& a, int b) {
	a = mul(a, b);
}

void dvup(int& a, int b) {
	a = dv(a, b);
}

int fact[FACTN], ifact[FACTN];

void computeFACT() {
	fact[0] = 1;
	for (int i = 1; i < FACTN; i++) fact[i] = mul(fact[i - 1], i);
	ifact[FACTN - 1] = dv(1, fact[FACTN - 1]);
	for (int i = FACTN - 2; i >= 0; i--) ifact[i] = mul(ifact[i + 1], i + 1);
}

int getCOMB(int n, int k) {
	return mul(fact[n], mul(ifact[k], ifact[n - k]));
}

int fastComb(int n, int k)
{
	if (k > n)
	{
		return 0;
	}
	// n is very big
	// k is small
	assert(0 <= k && k <= n);
	int up = 1;
	for (int i = 1; i <= k; i++)
	{
		mulup(up, n + 1 - i);
	}
	return mul(up, ifact[k]);
}

signed main()
{
	computeFACT();
#ifdef ONPC	
	FILE* stream;
	freopen_s(&stream, "input.txt", "r", stdin);
#else
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif

	int n;
	cin >> n;
	map<int, int> mp;
	vector<pair<int, int>> v(n);
	for (auto& it : v)
	{
		cin >> it.first >> it.second;
		mp[it.first] = 0;
		mp[it.second + 1] = 0;
	}
	vector<int> xs;
	int y = 0;
	for (auto& it : mp)
	{
		xs.push_back(it.first);
		it.second = y++;
	}
	vector<int> dim;
	for (int i = 0; i + 1 < (int)xs.size(); i++)
	{
		dim.push_back(xs[i + 1] - xs[i]);
	}
	assert((int)dim.size() == y - 1);
	y = (int)dim.size();
	for (auto& it : v)
	{
		assert(mp.count(it.first));
		assert(mp.count(it.second + 1));
		it.first = mp[it.first];
		it.second = mp[it.second + 1] - 1;
	}
	vector<vector<int>> dp(y, vector<int>(n + 1, 0));
	for (auto& seg : v)
	{
		int l = seg.first, r = seg.second;
		auto ndp = dp; // nu fac nimic aici
		// incep ceva nou aici
		for (int i = l; i <= r; i++)
		{
			addup(ndp[i][1], +1);
		}
		for (int i = 0; i < y; i++)
		{
			int orice = 0;
			for (int t = 1; t <= n; t++)
			{
				addup(orice, mul(dp[i][t], fastComb(dim[i], t)));
			}
			for (int j = i + 1; j < y; j++)
			{
				if (l <= j && j <= y)
				{
					addup(ndp[j][1], orice);
				}
			}
			for (int t = 1; t <= n; t++)
			{
				addup(ndp[i][t], dp[i][t - 1]);
			}
		}
		dp = ndp;
	}
	int sol = 0;
	for (int i = 0; i < y; i++)
	{
		for (int t = 0; t <= n; t++)
		{
			addup(sol, mul(dp[i][t], fastComb(dim[i], t)));
		}
	}
	cout << sol << "\n";

	return 0;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42