#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], bino[MAXN+10][MAXN+10], comb[MAXN+10], f[MAXN+10];
ll dp[MAXN+10][MAXN+10], ans;
int getcomp(int x) { return lower_bound(comp.begin(), comp.end(), x)-comp.begin(); }
ll mypow(ll x, ll y)
{
if(y==0) return 1;
if(y%2) return mypow(x, y-1)*x%MOD;
ll t=mypow(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]=mypow(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()-2;
ll a=comp[2]-comp[1];
memset(comb, 0, sizeof(comb)); memset(f, 0, sizeof(f));
comb[0]=1;
for(j=1; j<=a; j++) comb[j]=comb[j-1]*(a-j+1)%MOD*inv[j]%MOD;
for(j=1; j<=N; j++)
{
for(k=1; k<=j; k++)
{
f[j]+=comb[k]*bino[j-1][k-1]%MOD;
f[j]%=MOD;
}
}
int cnt=0;
for(i=1; i<=N; i++)
{
if(!(A[i]<=comp[1] && comp[1]<B[i])) continue;
cnt++;
dp[i][1]=f[cnt];
}
dp[0][1]=1;
for(i=2; i<=S; i++)
{
a=comp[i+1]-comp[i];
memset(comb, 0, sizeof(comb)); memset(f, 0, sizeof(f));
comb[0]=1;
for(j=1; j<=a; j++) comb[j]=comb[j-1]*(a-j+1)%MOD*inv[j]%MOD;
for(j=1; j<=N; j++)
{
for(k=1; k<=j; k++)
{
f[j]+=comb[k]*bino[j-1][k-1]%MOD;
f[j]%=MOD;
}
}
for(j=1; j<=N; j++)
{
int cnt=0;
for(k=j-1; k>=0; k--)
{
if(!(A[j]<=comp[i] && comp[i]<B[j])) continue;
cnt++;
dp[j][i]+=f[cnt]*dp[k][i-1]%MOD;
dp[j][i]%=MOD;
}
dp[j][i]+=dp[j][i-1]; dp[j][i]%=MOD;
}
dp[0][i]=1;
}
for(i=1; i<=N; i++) ans+=dp[i][S], ans%=MOD;
printf("%lld", ans);
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &N);
~~~~~^~~~~~~~~~
boat.cpp:43:14: 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 |
Runtime error |
22 ms |
14584 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
22 ms |
14584 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
21 ms |
14584 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
22 ms |
14584 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
2 |
Halted |
0 ms |
0 KB |
- |