#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=505;
const int M=2*N;
const int K=1000050;
const int mod=1e9+7;
int mul(int x, int y){ return (ll)x*y%mod;}
int add(int x, int y){ x+=y;return x>=mod?x-mod:x;}
int sub(int x, int y){ x-=y;return x<0?x+mod:x;}
int pow(int x, int k){ int ans=1;for(;k;k>>=1,x=mul(x,x)) if(k&1) ans=mul(ans,x);return ans;}
int inv(int x){ return pow(x,mod-2);}
int F[K],I[K];
int binom(int n, int k){ return n<k?0:mul(F[n],mul(I[k],I[n-k]));}
int dp[N],tmp[N][N],l[N],r[N];
void calc()
{
F[0]=1;for(int i=1;i<K;i++) F[i]=mul(F[i-1],i);
I[K-1]=inv(F[K-1]);for(int i=K-2;~i;i--) I[i]=mul(I[i+1],i+1);
}
int bc[N];
int main()
{
calc();
int n;
scanf("%i",&n);
vector<int> all;
for(int i=1;i<=n;i++)
{
scanf("%i %i",&l[i],&r[i]);
all.pb(l[i]);
all.pb(r[i]+1);
}
sort(all.begin(),all.end());
all.resize(unique(all.begin(),all.end())-all.begin());
dp[0]=1;
for(int t=1;t<all.size();t++)
{
int L=all[t]-all[t-1];
bc[0]=1;
for(int i=1;i<=n;i++) bc[i]=mul(bc[i-1],mul(L-i+1,inv(i)));
for(int i=1;i<=n;i++) dp[i]=add(dp[i],dp[i-1]);
for(int j=1;j<=n;j++)
{
for(int i=1;i<=n;i++)
{
if(all[t-1]<=r[i] && all[t-1]>=l[i]) tmp[i][j]=j==1?dp[i-1]:tmp[i-1][j-1];
else tmp[i][j]=0;
}
if(j==1) for(int i=n;i>=1;i--) dp[i]=sub(dp[i],dp[i-1]);
for(int i=1;i<=n;i++) dp[i]=add(dp[i],mul(tmp[i][j],bc[j]));
for(int i=1;i<=n;i++) tmp[i][j]=add(tmp[i][j],tmp[i-1][j]);
}
}
int ans=0;
for(int i=1;i<=n;i++) ans=add(ans,dp[i]);
printf("%i\n",ans);
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:38:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int t=1;t<all.size();t++)
~^~~~~~~~~~~
boat.cpp:27:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%i",&n);
~~~~~^~~~~~~~~
boat.cpp:31:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%i %i",&l[i],&r[i]);
~~~~~^~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2061 ms |
9088 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2061 ms |
9088 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
39 ms |
8400 KB |
Output is correct |
2 |
Correct |
38 ms |
8440 KB |
Output is correct |
3 |
Correct |
38 ms |
8316 KB |
Output is correct |
4 |
Correct |
38 ms |
8448 KB |
Output is correct |
5 |
Correct |
38 ms |
8320 KB |
Output is correct |
6 |
Correct |
39 ms |
8312 KB |
Output is correct |
7 |
Correct |
42 ms |
8448 KB |
Output is correct |
8 |
Correct |
41 ms |
8396 KB |
Output is correct |
9 |
Correct |
38 ms |
8440 KB |
Output is correct |
10 |
Correct |
44 ms |
8368 KB |
Output is correct |
11 |
Correct |
41 ms |
8440 KB |
Output is correct |
12 |
Correct |
44 ms |
8440 KB |
Output is correct |
13 |
Correct |
38 ms |
8440 KB |
Output is correct |
14 |
Correct |
38 ms |
8448 KB |
Output is correct |
15 |
Correct |
38 ms |
8320 KB |
Output is correct |
16 |
Correct |
32 ms |
8440 KB |
Output is correct |
17 |
Correct |
33 ms |
8440 KB |
Output is correct |
18 |
Correct |
31 ms |
8384 KB |
Output is correct |
19 |
Correct |
31 ms |
8320 KB |
Output is correct |
20 |
Correct |
30 ms |
8364 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
2061 ms |
9088 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |