제출 #551893

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
551893		nafis_shifat	Boat (APIO16_boat)	C++17	9 / 100	318 ms	20916 KiB

boat

#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
using namespace std;
const int mxn=1500+5;
const int inf=1e9;
const ll mod = 1e9 + 7;
ll bigmod(ll a, ll b) {
	if(b == 0) return 1;
	int mid = b / 2;

	ll res = bigmod(a, mid);
	res = res * res % mod;
	if(b % 2 == 1) return a * res % mod;
	return res;
}

ll last[mxn][mxn] = {};
ll dp[mxn][mxn] = {};
ll sum[mxn][mxn] = {};

ll fact[mxn], inv[mxn];
int main() {
	fact[0] = 1;
	inv[0] = 1;

	for(int i = 1; i < mxn; i++) {
		fact[i] = fact[i - 1] * i % mod;
		inv[i] = bigmod(fact[i], mod - 2) % mod;
	}
	int n;
	cin >> n;
	int a[n + 1], b[n + 1];
	int l[n + 1], r[n + 1];
	vector<int> v;
	v.push_back(0);
	for(int i = 1; i <= n; i++) {
		cin >> a[i] >> b[i];
		v.push_back(a[i]);
		v.push_back(a[i] - 1);
		v.push_back(b[i]);

	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());

	int len[v.size() + 2];
	for(int i = 1; i < v.size(); i++) len[i] = v[i] - v[i - 1];


	for(int i = 1; i <= n; i++) {
		l[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin();
		r[i] = lower_bound(v.begin(), v.end(), b[i]) - v.begin();
	}

	dp[0][0] = 1;
	for(int i = 0; i < v.size(); i++) sum[i][0] = 1;

	ll ans = 0;

    for(int p = 1; p <= n; p++) {
    	for(int i = l[p]; i <= r[p]; i++) {
    		ll tot = len[i];
    		ll found = 1;

    		for(int j = p - 1; j >= 0; j--) {
    			dp[i][j] = sum[i - 1][j] * tot % mod;
    			sum[i][p] = (sum[i][p] + dp[i][j]) % mod;

    			if(l[j] >= i && r[j] <= i) {
    				found++;
    				if(found >= len[i]) continue;
    				tot += (len[i] - found + 1) * inv[found] % mod;
    				tot %= mod;
    			}

    		}
    	}

    	for(int i = l[p]; i < v.size(); i++) sum[i][p] = (sum[i][p] + sum[i - 1][p]) % mod;

    	ans += sum[v.size() - 1][p];

    }

    cout<<ans % mod<<endl;


	
}

컴파일 시 표준 에러 (stderr) 메시지

boat.cpp: In function 'int main()':
boat.cpp:48:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |  for(int i = 1; i < v.size(); i++) len[i] = v[i] - v[i - 1];
      |                 ~~^~~~~~~~~~
boat.cpp:57:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |  for(int i = 0; i < v.size(); i++) sum[i][0] = 1;
      |                 ~~^~~~~~~~~~
boat.cpp:80:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |      for(int i = l[p]; i < v.size(); i++) sum[i][p] = (sum[i][p] + sum[i - 1][p]) % mod;
      |                        ~~^~~~~~~~~~

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