Submission #262449

#	Time	Username	Problem	Language	Result	Execution time	Memory
262449		yuma220284	Boat (APIO16_boat)	C++14	9 / 100	6 ms	4360 KiB

boat

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

constexpr long long MOD = 1000000007;

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int N;
	cin >> N;
	vector<long long> A(N), B(N), X;
	X.push_back(0);
	for (int i = 0; i < N; i++) {
		cin >> A[i] >> B[i];
		B[i]++;
		X.push_back(A[i]), X.push_back(B[i]);
	}
	sort(X.begin(), X.end());
	X.erase(unique(X.begin(), X.end()), X.end());
	for (int i = 0; i < N; i++) {
		A[i] = lower_bound(X.begin(), X.end(), A[i]) - X.begin();
		B[i] = lower_bound(X.begin(), X.end(), B[i]) - X.begin();
	}
	vector<vector<long long> > DP(N + 1, vector<long long>(X.size() - 1, 0));
	DP[0][0] = 1;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < X.size() - 1; j++) DP[i + 1][j] = DP[i][j];
		long long SUM = 0;
		for (int j = 0; j < A[i]; j++) SUM += DP[i][j], SUM %= MOD;
		for (int j = A[i]; j < B[i]; j++) {
			DP[i + 1][j] += SUM * (X[j + 1] - X[j]);
			DP[i + 1][j] %= MOD;
			SUM += DP[i][j];
			SUM %= MOD;
		}
	}
	long long ANS = 0;
	for (int j = 1; j < X.size() - 1; j++) {
		ANS += DP[N][j];
		ANS %= MOD;
	}
	cout << ANS << endl;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:27:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |   for (int j = 0; j < X.size() - 1; j++) DP[i + 1][j] = DP[i][j];
      |                   ~~^~~~~~~~~~~~~~
boat.cpp:38:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |  for (int j = 1; j < X.size() - 1; j++) {
      |                  ~~^~~~~~~~~~~~~~

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