#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 1000;
const ll MOD = 1e9+7;
int N, S, A[MAXN+10], B[MAXN+10];
vector<int> comp;
ll inv[MAXN+10], dp[MAXN+10][MAXN+10], bino[MAXN+10][MAXN+10], comb[MAXN+10], f[MAXN+10], ans;
int getcomp(int x) { return lower_bound(comp.begin(), comp.end(), x)-comp.begin(); }
ll pow(ll x, ll y)
{
if(y==0) return 1;
if(y%2) return pow(x, y-1)*x%MOD;
ll t=pow(x, y/2);
return t*t%MOD;
}
int main()
{
int i, j, k;
bino[0][0]=1;
for(i=1; i<=MAXN; i++) for(j=0; j<=i; j++)
{
if(j==0 || j==i) bino[i][j]=1;
else bino[i][j]=(bino[i-1][j]+bino[i-1][j-1])%MOD;
}
inv[0]=1;
for(i=1; i<=MAXN; i++) inv[i]=inv[i-1]*pow(i, MOD-2);
scanf("%d", &N);
for(i=1; i<=N; i++)
{
scanf("%d%d", &A[i], &B[i]);
B[i]++;
comp.push_back(A[i]);
comp.push_back(B[i]);
}
comp.push_back(0);
sort(comp.begin(), comp.end());
comp.erase(unique(comp.begin(), comp.end()), comp.end());
S=comp.size()-1;
for(i=0; i<S; i++) dp[0][i]=1;
for(i=1; i<S; i++)
{
memset(comb, 0, sizeof(comb));
memset(f, 0, sizeof(f));
ll sz=comp[i+1]-comp[i]; comb[0]=1;
for(j=1; j<=N; j++) comb[j]=comb[j-1]*(sz+1-j)%MOD*inv[j]%MOD;
for(j=1; j<=N; j++) for(k=1; k<=j; k++) f[j]=(f[j]+comb[k]*bino[j-1][k-1])%MOD;
for(j=1; j<=N; j++)
{
if(getcomp(A[j])<=comp[i] && comp[i]<getcomp(B[j]))
{
int cnt=1;
dp[j][i]=1;
for(k=1; k<j; k++)
{
if(sz<cnt) break;
dp[j][i]+=dp[j-k][i-1]*f[cnt]%MOD;
dp[j][i]%=MOD;
if((getcomp(A[j-k]<=comp[i] && comp[i]<getcomp(B[j-k])))) cnt++;
}
}
dp[j][i]+=dp[j][i-1];
dp[j][i]%=MOD;
}
}
for(i=1; i<=N; i++) ans=(ans+dp[i][S-1])%MOD;
printf("%lld", ans);
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &N);
~~~~~^~~~~~~~~~
boat.cpp:42:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d", &A[i], &B[i]);
~~~~~^~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
776 ms |
11508 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
776 ms |
11508 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
17 ms |
7832 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
776 ms |
11508 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |