제출 #667324

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
667324		NothingXD	Boat (APIO16_boat)	C++17	58 / 100	2068 ms	7460 KiB

boat

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

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
/*typedef __uint128_t L;
struct FastMod {
  ull b, m;
  FastMod(ull b) : b(b), m(ull((L(1) << 64) / b)) {}
  ull reduce(ull a) {
    ull q = (ull)((L(m) * a) >> 64);
    ull r = a - q * b; // can be proven that 0 <= r < 2*b
    return r >= b ? r - b : r;
  }
};
FastMod FM(2);*/
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
	cerr << " " << H;
	debug_out(T...);
}

#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#define all(x) x.begin(), x.end()
#define MP(x, y) make_pair(x, y)
#define F first
#define S second

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int maxn = 500 + 10;
const int mod = 1e9 + 7;
int n, dp[maxn][maxn << 1], C[maxn][maxn], CC[maxn << 1][maxn], f[maxn << 1][maxn], inv[maxn], a[maxn], b[maxn];
vector<int> num;

int add(int x, int y){
	int res = x + y;
	if (res >= mod) return res - mod;
	if (res < 0) return res + mod;
	return res;
}

int pwr(int a, int b){
	int res = 1;
	for (; b; b>>=1, a = 1ll * a * a % mod) if (b & 1) res = 1ll * res * a % mod;
	return res;
}

int main(){
	ios_base::sync_with_stdio(false); cin.tie(0);

	cin >> n;

	for (int i = 1; i <= n; i++){
		cin >> a[i] >> b[i];
		num.push_back(a[i]);
		num.push_back(b[i]+1);
	}

	num.push_back(0);

	sort(all(num));
	num.resize(distance(num.begin(), unique(all(num))));

	for (int i = 1; i <= n; i++){
		inv[i] = pwr(i, mod-2);
	}

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


	for (int i = 0; i + 1 < num.size(); i++){
		int tmp = num[i+1] - num[i];
		for (int j = 1; j <= n; j++){
			if (j > tmp) continue;
			CC[i][j] = 1;
			for (int k = 1; k <= j; k++){
				CC[i][j] = 1ll * CC[i][j] * (tmp - k + 1) % mod * inv[k] % mod;
			}
		}
	}
	for (int i = 0; i + 1 < num.size(); i++){
		int tmp = num[i+1] - num[i];
		for (int j = 1; j <= n; j++){
			for (int k = 1; k <= j; k++){
				f[i][j] = add(f[i][j], 1ll * CC[i][k] * C[j-1][k-1] % mod);
			}
		}
	}


	for (int i = 0; i + 1 < num.size(); i++) dp[0][i] = 1;
	for (int i = 1; i <= n; i++){
		for (int j = 1; j + 1 < num.size(); j++){
			dp[i][j] = dp[i][j-1];
			if (a[i] > num[j] || b[i] < num[j]) continue;
			int cnt = 1;
			for (int k = i-1; ~k; k--){
				dp[i][j] = add(dp[i][j], 1ll * dp[k][j-1] * f[j][cnt] % mod);
				if (a[k] <= num[j] && num[j] <= b[k]) cnt++;
			}
		}
	}

	int ans = 0;
	for (int i = 1; i <= n; i++){
		ans = add(ans, dp[i][num.size()-2]);
	}
	cout << ans << '\n';
}

컴파일 시 표준 에러 (stderr) 메시지

boat.cpp: In function 'int main()':
boat.cpp:83:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |  for (int i = 0; i + 1 < num.size(); i++){
      |                  ~~~~~~^~~~~~~~~~~~
boat.cpp:93:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |  for (int i = 0; i + 1 < num.size(); i++){
      |                  ~~~~~~^~~~~~~~~~~~
boat.cpp:94:7: warning: unused variable 'tmp' [-Wunused-variable]
   94 |   int tmp = num[i+1] - num[i];
      |       ^~~
boat.cpp:103:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |  for (int i = 0; i + 1 < num.size(); i++) dp[0][i] = 1;
      |                  ~~~~~~^~~~~~~~~~~~
boat.cpp:105:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  105 |   for (int j = 1; j + 1 < num.size(); j++){
      |                   ~~~~~~^~~~~~~~~~~~

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