oj.uz

Submission #90536

# Submission time Handle Problem Language Result Execution time Memory
90536 2018-12-22T09:21:07 Z szawinis Boat (APIO16_boat) C++17
27 / 100
 435 ms 6912 KB 
/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

#include <bits/stdc++.h>
using namespace std;
#define long long long
const long MOD = 1e9+7, LINF = 1e18 + 1e16;
const int INF = 1e9+1;
const double EPS = 1e-10;
const int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
const int N = 510;

class APIO16_boat {

	void add(long &a, long b) {
		a += b;
		if(a >= MOD) a -= MOD;
	}
	long mul(long a, long b) { return a*b % MOD; }
	long modPow(long b, long e) {
		if(e == 0) return 1;
		if(e == 1) return b;
		return mul(modPow(mul(b, b), e >> 1), modPow(b, e & 1));
	}

	int n, a[N], b[N];
	pair<int,int> segs[N];
	vector<int> vals;
	unordered_map<int, int> rev;

	long ans, inv[N], C[N][N], f[N][N], dp[N][N];

public:

	long brute() {
		vector<vector<long> > dp(100, vector<long>(100));
		dp[0][0] = 1;
		long ans = 0;
		for(int i = 1; i <= n; i++) {
			for(int j = a[i]; j <= b[i]; j++) {
				for(int k = 0; k < i; k++) {
					for(int x = a[k]; x <= b[k] && x < j; x++) {
						dp[i][j] += dp[k][x];
					}
				}
				ans += dp[i][j];
			}
		}
		return ans;
	}

	void solve(istream &cin, ostream &cout) {
		cin >> n;
		vals.push_back(0);
		for(int i = 1; i <= n; i++) {
			cin >> a[i] >> b[i];
			vals.push_back(a[i]);
			vals.push_back(b[i]+1);
		}
		sort(vals.begin(), vals.end());
		vals.resize(unique(vals.begin(), vals.end()) - vals.begin());
		for(int i = 0; i < vals.size(); i++) rev[vals[i]] = i;
		for(int i = 1; i <= n; i++) segs[i] = {rev[a[i]], rev[b[i]+1]};

		inv[0] = 1;
		for(int i = 1; i <= n; i++) inv[i] = modPow(i, MOD-2);
		C[0][0] = 1;
		for(int i = 1; i <= n; i++) {
			C[i][0] = C[i][i] = 1;
			for(int j = 1; j < i; j++) {
				add(C[i][j], C[i-1][j-1]);
				add(C[i][j], C[i-1][j]);
			}
		}

		for(int j = 1; j < vals.size()-1; j++) {
			f[j][0] = 1;
			for(int cnt = 1; cnt <= min(vals[j+1] - vals[j], n); cnt++) {
				f[j][cnt] = mul(f[j][cnt - 1], vals[j+1] - vals[j] - (cnt - 1));
				f[j][cnt] = mul(f[j][cnt], inv[cnt]);
			}
//			for(int cnt = 1; cnt <= n; cnt++) cout << j << ' ' << cnt << ' ' << vals[j+1] - vals[j] << ' ' << f[j][cnt] << endl;
//			cout << endl;
			for(int cnt = n; cnt >= 1; cnt--) {
				for(int x = 1; x <= min(cnt-1, n); x++) {
					add(f[j][cnt], mul(f[j][x], C[cnt-1][x-1]));
				}
			}
//			for(int cnt = 1; cnt <= n; cnt++) cout << j << ' ' << cnt << ' ' << vals[j+1] - vals[j] << ' ' << f[j][cnt] << endl;
//			cout << endl;
		}

//		for(int x: vals) cout << x << ' ';
//		cout << endl;
//		for(int i = 1; i <= n; i++) cout << segs[i].first << ' ' << segs[i].second << endl;

		for(int j = 0; j < vals.size(); j++) dp[0][j] = 1;
		for(int i = 1; i <= n; i++) {
			for(int j = segs[i].first; j < segs[i].second; j++) {
				int cnt = 0;
				for(int k = i-1; k >= 0; k--) {
					cnt += segs[k+1].first <= j && j < segs[k+1].second;
					add(dp[i][j], mul(dp[k][j-1], f[j][cnt]));
//					cout << i << ' ' << j << ' ' << k << ' ' << cnt << ' ' << dp[k][j-1] << ' ' << f[j][cnt] << ' ' << dp[k][j-1] * f[j][cnt] << endl;
				}
//				cout << i << ' ' << j << ' ' << dp[i][j] << endl;
			}
			for(int j = 1; j < vals.size(); j++) add(dp[i][j], dp[i][j-1]);
			add(ans, dp[i][vals.size() - 1]);
		}
		cout << ans << endl;
//		cout << brute() << endl;
	}
};

class Solver {
public:
	void solve(std::istream& in, std::ostream& out) {
	    APIO16_boat *obj = new APIO16_boat();
		obj->solve(in, out);
		delete obj;
	}
};

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	Solver solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
	return 0;
}

Compilation message

boat.cpp: In member function 'void APIO16_boat::solve(std::istream&, std::ostream&)':
boat.cpp:65:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < vals.size(); i++) rev[vals[i]] = i;
                  ~~^~~~~~~~~~~~~
boat.cpp:79:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 1; j < vals.size()-1; j++) {
                  ~~^~~~~~~~~~~~~~~
boat.cpp:100:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < vals.size(); j++) dp[0][j] = 1;
                  ~~^~~~~~~~~~~~~
boat.cpp:111:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j = 1; j < vals.size(); j++) add(dp[i][j], dp[i][j-1]);
                   ~~^~~~~~~~~~~~~

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Incorrect 435 ms 6648 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Incorrect 435 ms 6648 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 6648 KB Output is correct
2 Correct 12 ms 6648 KB Output is correct
3 Correct 12 ms 6648 KB Output is correct
4 Correct 12 ms 6796 KB Output is correct
5 Correct 12 ms 6852 KB Output is correct
6 Correct 14 ms 6852 KB Output is correct
7 Correct 12 ms 6852 KB Output is correct
8 Correct 12 ms 6852 KB Output is correct
9 Correct 13 ms 6852 KB Output is correct
10 Correct 13 ms 6852 KB Output is correct
11 Correct 12 ms 6912 KB Output is correct
12 Correct 12 ms 6912 KB Output is correct
13 Correct 12 ms 6912 KB Output is correct
14 Correct 12 ms 6912 KB Output is correct
15 Correct 12 ms 6912 KB Output is correct
16 Correct 10 ms 6912 KB Output is correct
17 Correct 10 ms 6912 KB Output is correct
18 Correct 10 ms 6912 KB Output is correct
19 Correct 9 ms 6912 KB Output is correct
20 Correct 10 ms 6912 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Incorrect 435 ms 6648 KB Output isn't correct
2 Halted 0 ms 0 KB -