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답안 #110591

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
110591 2019-05-11T09:18:55 Z Pro_ktmr Boat (APIO16_boat) C++14
0 / 100
 28 ms 8440 KB 
#include"bits/stdc++.h"
using namespace std;
#define LL long long
#define PB push_back
#define MP make_pair

const LL MOD = 1000000007;

//累乗 O(log N)
long long power(long long x, int N){
	if(N == 1) return x;
	long long tmp = power(x, N/2);
	if(N%2 == 0) return tmp * tmp % MOD;
	else return tmp * tmp % MOD * x % MOD;
}

//逆元 O(log x)
long long inverse(long long x){
	return power(x, MOD-2);
}

//コンビネーション
struct Combination{
private:
	int N;
	vector<long long> fact, inv;
public:
	void init(int n){ //初期化する O(N)
		N = n;
		fact.push_back(1);
		inv.push_back(1);
		for(long long i=1; i<=N; i++){
			fact.push_back(fact.back()*i%MOD);
			inv.push_back(inverse(fact.back()));
		}
	}
	long long comb(int n, int k){ //nCkを求める O(1)
		return fact[n] * inv[k] % MOD * inv[n-k] % MOD;
	}
};

Combination comb;

int N, a[500], b[500], A[500], B[500];
vector<int> v;
vector<int> ls[1000];

LL culc(LL range, int num){
	if(num == 1) return range;
	LL ret = 0;
	LL tmp1 = range;
	LL tmp2 = range-1;
	for(int i=0; i<=num-2; i++){ //中のを何個使うか
		if(tmp2 == 0) break;
		tmp1 = tmp1 * tmp2 % MOD;
		tmp1 = tmp1 * inverse(i+2) % MOD;
		tmp2--;
		ret += tmp1 * comb.comb(num-2, i) % MOD;
	}
	return ret % MOD;
}

//a:=区間、b:=学校
LL dp[1000][500][2];
LL solve(int a, int b, int ok){
	if(a == v.size()-1) return 1;
	if(ok == 0 && b == N) return 0;
	if(ok == 1 && b == N) return 1;
	if(dp[a][b][ok] != -1) return dp[a][b][ok];
	if(ok == 0){
		dp[a][b][ok] = solve(a, b+1, 0);
		if(A[b] <= a && a < B[b]){
			int idx = lower_bound(ls[a].begin(), ls[a].end(), b) - ls[a].begin();
			LL range = v[a+1] - v[a];
			LL c = culc(range, 1);
			for(int i=idx; i<ls[a].size()-1; i++){
				dp[a][b][ok] += c*solve(a+1, ls[a][i]+1, 1);
				c *= 2;
				dp[a][b][ok] %= MOD;
			}
		}
	}
	else{
		dp[a][b][ok] = solve(a+1, b, 1);
		dp[a][b][ok] += solve(a, b, 0);
		dp[a][b][ok] %= MOD;
	}
	return dp[a][b][ok];
}

int main(){
	scanf("%d", &N);
	for(int i=0; i<N; i++){
		scanf("%d%d", a+i, b+i);
		b[i]++;
		v.PB(a[i]);
		v.PB(b[i]);
	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
	for(int i=0; i<N; i++){
		A[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin();
		B[i] = lower_bound(v.begin(), v.end(), b[i]) - v.begin();
		for(int j=A[i]; j<B[i]; j++) ls[j].PB(i);
	}
	for(int i=0; i<v.size(); i++){
		ls[i].PB(N);
		for(int j=0; j<N; j++) dp[i][j][0] = -1;
		for(int j=0; j<N; j++) dp[i][j][1] = -1;
	}
	comb.init(N);
	printf("%d\n", (solve(0, 0, 1)-1+MOD)%MOD);
}

Compilation message

boat.cpp: In function 'long long int solve(int, int, int)':
boat.cpp:66:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(a == v.size()-1) return 1;
     ~~^~~~~~~~~~~~~
boat.cpp:76:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=idx; i<ls[a].size()-1; i++){
                   ~^~~~~~~~~~~~~~~
boat.cpp: In function 'int main()':
boat.cpp:106:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<v.size(); i++){
               ~^~~~~~~~~
boat.cpp:112:43: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
  printf("%d\n", (solve(0, 0, 1)-1+MOD)%MOD);
                 ~~~~~~~~~~~~~~~~~~~~~~~~~~^
boat.cpp:92:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
boat.cpp:94:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", a+i, b+i);
   ~~~~~^~~~~~~~~~~~~~~~~~

Subtask #1
0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 8320 KB Output is correct
2 Correct 27 ms 8320 KB Output is correct
3 Correct 28 ms 8440 KB Output is correct
4 Correct 22 ms 8320 KB Output is correct
5 Correct 23 ms 8320 KB Output is correct
6 Correct 18 ms 8320 KB Output is correct
7 Correct 20 ms 8320 KB Output is correct
8 Correct 21 ms 8320 KB Output is correct
9 Correct 17 ms 8320 KB Output is correct
10 Correct 19 ms 8320 KB Output is correct
11 Correct 17 ms 8320 KB Output is correct
12 Correct 18 ms 8320 KB Output is correct
13 Correct 18 ms 8320 KB Output is correct
14 Correct 24 ms 8320 KB Output is correct
15 Correct 19 ms 8320 KB Output is correct
16 Incorrect 5 ms 1792 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 8320 KB Output is correct
2 Correct 27 ms 8320 KB Output is correct
3 Correct 28 ms 8440 KB Output is correct
4 Correct 22 ms 8320 KB Output is correct
5 Correct 23 ms 8320 KB Output is correct
6 Correct 18 ms 8320 KB Output is correct
7 Correct 20 ms 8320 KB Output is correct
8 Correct 21 ms 8320 KB Output is correct
9 Correct 17 ms 8320 KB Output is correct
10 Correct 19 ms 8320 KB Output is correct
11 Correct 17 ms 8320 KB Output is correct
12 Correct 18 ms 8320 KB Output is correct
13 Correct 18 ms 8320 KB Output is correct
14 Correct 24 ms 8320 KB Output is correct
15 Correct 19 ms 8320 KB Output is correct
16 Incorrect 5 ms 1792 KB Output isn't correct
17 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 4 ms 1536 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 8320 KB Output is correct
2 Correct 27 ms 8320 KB Output is correct
3 Correct 28 ms 8440 KB Output is correct
4 Correct 22 ms 8320 KB Output is correct
5 Correct 23 ms 8320 KB Output is correct
6 Correct 18 ms 8320 KB Output is correct
7 Correct 20 ms 8320 KB Output is correct
8 Correct 21 ms 8320 KB Output is correct
9 Correct 17 ms 8320 KB Output is correct
10 Correct 19 ms 8320 KB Output is correct
11 Correct 17 ms 8320 KB Output is correct
12 Correct 18 ms 8320 KB Output is correct
13 Correct 18 ms 8320 KB Output is correct
14 Correct 24 ms 8320 KB Output is correct
15 Correct 19 ms 8320 KB Output is correct
16 Incorrect 5 ms 1792 KB Output isn't correct
17 Halted 0 ms 0 KB -