#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#pragma GCC optimize ("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
const int nmax=1e3+42,mod=1e9+7;
int my_pow(long long a,int b)
{
long long ret=1;
while(b)
{
if(b%2)ret=ret*a%mod;
a=a*a%mod;
b=b/2;
}
return ret;
}
int n;
pair<int,int> inp[nmax];
set< pair<int,int> > seen;
pair<int,int> groups[nmax];
int pointer=0;
int inv[nmax];
int dp[nmax][nmax][2];
int coeff[nmax][nmax];
void rec(int which_number,int last_used_group,bool can_place_zero)
{
for(int which_number=n+1;which_number>=1;which_number--)
for(int last_used_group=pointer;last_used_group>=0;last_used_group--)
for(int can_place_zero=0;can_place_zero<2;can_place_zero++)
{
if(which_number>n){dp[which_number][last_used_group][can_place_zero]=1;continue;}//properly chosen
if(last_used_group==pointer){dp[which_number][last_used_group][can_place_zero]=can_place_zero;continue;}//skipped too much
long long ret=0;
//place zero
if(can_place_zero)ret=(ret+dp[which_number+1][last_used_group][1])%mod;
//place non-zero for other group
ret=(ret+dp[which_number][last_used_group+1][0])%mod;//ignore this group
//place non-zero
if(inp[which_number].first<=groups[last_used_group+1].first&&groups[last_used_group+1].second<=inp[which_number].second)
{
int nums=0;
for(int use=which_number;use<=n;use++)
{
if(inp[use].first<=groups[last_used_group+1].first&&groups[last_used_group+1].second<=inp[use].second)
{
nums++;
ret=(ret+1LL*coeff[last_used_group+1][nums]*dp[use+1][last_used_group+1][1])%mod;
}
//cout<<"which_number= "<<which_number<<" last_used_group= "<<last_used_group<<" use= "<<use<<" mult= "<<coeff[last_used_group+1][nums]<<" can_place_zero= "<<can_place_zero<<" finish= "<<rec(use+1,last_used_group+1,1)<<endl;
}
}
dp[which_number][last_used_group][can_place_zero]=ret;
}
//cout<<which_number<<" "<<last_used_group<<" "<<can_place_zero<<" -> "<<ret<<endl;
}
int C[nmax][nmax];
int ask_C(int n_,int k_)
{
if(0>k_||k_>n_)return 0;
return C[n_][k_];
}
int main()
{
for(int i=0;i<nmax;i++)
for(int j=0;j<=i;j++)
if(j==0||j==i)C[i][j]=1;
else C[i][j]=(C[i-1][j]+C[i-1][j-1])%mod;
scanf("%i",&n);
for(int i=1;i<nmax;i++)
{
inv[i]=my_pow(i,mod-2);
}
int prv=1e9;
for(int i=1;i<=n;i++)
{
scanf("%i%i",&inp[i].first,&inp[i].second);
seen.insert({inp[i].first,-1});
seen.insert({inp[i].second,0});
prv=min(prv,inp[i].first);
prv=min(prv,inp[i].second);
}
for(auto k:seen)
{
int other=k.first+k.second;
if(prv<=other)
{
pointer++;
groups[pointer]={prv,other};
prv=other+1;
}
}
/*
for(int i=1;i<=n;i++)
for(int j=1;j<=pointer;j++)
{
int le=max(inp[i].first,groups[j].first);
int ri=min(inp[i].second,groups[j].second);
if(le>ri)continue;
assert(le==groups[j].first&&ri==groups[j].second);
}
cout<<"---"<<endl;
for(int i=1;i<=pointer;i++)cout<<groups[i].first<<" "<<groups[i].second<<endl;
*/
for(int which=1;which<=pointer;which++)
for(int nums=1;nums<=n;nums++)
{
int total=groups[which].second-groups[which].first+1;
if(nums==1)coeff[which][1]=total;
else
{
long long coeff_help=total;
for(int zero=nums-2;zero>=0;zero--)
{
if(total<nums-zero)coeff_help=0;
else if(total==nums-zero)coeff_help=1;
else coeff_help=coeff_help*(total-(nums-zero)+1)%mod*inv[nums-zero]%mod;
//cout<<"zero= "<<zero<<" "<<total-(nums-zero)+1<<" , "<<nums-zero<<" actual= "<<inv[nums-zero]<<endl;
//cout<<"zero= "<<zero<<" "<<coeff_help<<" "<<ask_C(total,nums-zero)<<endl;
//if(coeff_help!=ask_C(total,nums-zero))system("pause");
coeff[which][nums]=(coeff[which][nums]+1LL*ask_C(nums-2,zero)*coeff_help)%mod;
}
}
//cout<<which<<" "<<nums<<" -> "<<coeff[which][nums]<<endl;
//cout<<"---"<<endl;
}
rec(1,0,1);
int out=dp[1][0][1];//rec(1,0,1);
out=(out-1+mod)%mod;
printf("%i\n",out);
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:89:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%i",&n);
~~~~~^~~~~~~~~
boat.cpp:99:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%i%i",&inp[i].first,&inp[i].second);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1078 ms |
12768 KB |
Output is correct |
2 |
Correct |
1070 ms |
12984 KB |
Output is correct |
3 |
Correct |
1058 ms |
12984 KB |
Output is correct |
4 |
Correct |
1060 ms |
12792 KB |
Output is correct |
5 |
Correct |
1068 ms |
12920 KB |
Output is correct |
6 |
Correct |
1071 ms |
13000 KB |
Output is correct |
7 |
Correct |
1069 ms |
12920 KB |
Output is correct |
8 |
Correct |
1062 ms |
12988 KB |
Output is correct |
9 |
Correct |
1053 ms |
13048 KB |
Output is correct |
10 |
Correct |
1055 ms |
12928 KB |
Output is correct |
11 |
Correct |
1058 ms |
12968 KB |
Output is correct |
12 |
Correct |
1091 ms |
12920 KB |
Output is correct |
13 |
Correct |
1090 ms |
12836 KB |
Output is correct |
14 |
Correct |
1085 ms |
12924 KB |
Output is correct |
15 |
Correct |
1051 ms |
12896 KB |
Output is correct |
16 |
Correct |
193 ms |
8056 KB |
Output is correct |
17 |
Correct |
207 ms |
8184 KB |
Output is correct |
18 |
Correct |
198 ms |
8056 KB |
Output is correct |
19 |
Correct |
207 ms |
8184 KB |
Output is correct |
20 |
Correct |
203 ms |
8060 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1078 ms |
12768 KB |
Output is correct |
2 |
Correct |
1070 ms |
12984 KB |
Output is correct |
3 |
Correct |
1058 ms |
12984 KB |
Output is correct |
4 |
Correct |
1060 ms |
12792 KB |
Output is correct |
5 |
Correct |
1068 ms |
12920 KB |
Output is correct |
6 |
Correct |
1071 ms |
13000 KB |
Output is correct |
7 |
Correct |
1069 ms |
12920 KB |
Output is correct |
8 |
Correct |
1062 ms |
12988 KB |
Output is correct |
9 |
Correct |
1053 ms |
13048 KB |
Output is correct |
10 |
Correct |
1055 ms |
12928 KB |
Output is correct |
11 |
Correct |
1058 ms |
12968 KB |
Output is correct |
12 |
Correct |
1091 ms |
12920 KB |
Output is correct |
13 |
Correct |
1090 ms |
12836 KB |
Output is correct |
14 |
Correct |
1085 ms |
12924 KB |
Output is correct |
15 |
Correct |
1051 ms |
12896 KB |
Output is correct |
16 |
Correct |
193 ms |
8056 KB |
Output is correct |
17 |
Correct |
207 ms |
8184 KB |
Output is correct |
18 |
Correct |
198 ms |
8056 KB |
Output is correct |
19 |
Correct |
207 ms |
8184 KB |
Output is correct |
20 |
Correct |
203 ms |
8060 KB |
Output is correct |
21 |
Correct |
748 ms |
12476 KB |
Output is correct |
22 |
Correct |
758 ms |
12540 KB |
Output is correct |
23 |
Correct |
737 ms |
12604 KB |
Output is correct |
24 |
Correct |
748 ms |
12540 KB |
Output is correct |
25 |
Correct |
778 ms |
12408 KB |
Output is correct |
26 |
Correct |
960 ms |
12408 KB |
Output is correct |
27 |
Correct |
969 ms |
12408 KB |
Output is correct |
28 |
Correct |
924 ms |
12408 KB |
Output is correct |
29 |
Correct |
930 ms |
12280 KB |
Output is correct |
30 |
Correct |
1030 ms |
12916 KB |
Output is correct |
31 |
Correct |
1036 ms |
13020 KB |
Output is correct |
32 |
Correct |
1038 ms |
12920 KB |
Output is correct |
33 |
Correct |
1050 ms |
12920 KB |
Output is correct |
34 |
Correct |
1062 ms |
12920 KB |
Output is correct |
35 |
Correct |
1042 ms |
12792 KB |
Output is correct |
36 |
Correct |
1044 ms |
12876 KB |
Output is correct |
37 |
Correct |
1061 ms |
12844 KB |
Output is correct |
38 |
Correct |
1052 ms |
12920 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
22 ms |
6016 KB |
Output is correct |
2 |
Correct |
21 ms |
6004 KB |
Output is correct |
3 |
Correct |
22 ms |
6016 KB |
Output is correct |
4 |
Correct |
21 ms |
6016 KB |
Output is correct |
5 |
Correct |
22 ms |
6016 KB |
Output is correct |
6 |
Correct |
23 ms |
6016 KB |
Output is correct |
7 |
Correct |
23 ms |
6016 KB |
Output is correct |
8 |
Correct |
23 ms |
6016 KB |
Output is correct |
9 |
Correct |
24 ms |
6008 KB |
Output is correct |
10 |
Correct |
23 ms |
6016 KB |
Output is correct |
11 |
Correct |
22 ms |
6016 KB |
Output is correct |
12 |
Correct |
27 ms |
6008 KB |
Output is correct |
13 |
Correct |
21 ms |
6016 KB |
Output is correct |
14 |
Correct |
22 ms |
6008 KB |
Output is correct |
15 |
Correct |
22 ms |
6016 KB |
Output is correct |
16 |
Correct |
15 ms |
5632 KB |
Output is correct |
17 |
Correct |
15 ms |
5504 KB |
Output is correct |
18 |
Correct |
15 ms |
5632 KB |
Output is correct |
19 |
Correct |
15 ms |
5504 KB |
Output is correct |
20 |
Correct |
15 ms |
5504 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1078 ms |
12768 KB |
Output is correct |
2 |
Correct |
1070 ms |
12984 KB |
Output is correct |
3 |
Correct |
1058 ms |
12984 KB |
Output is correct |
4 |
Correct |
1060 ms |
12792 KB |
Output is correct |
5 |
Correct |
1068 ms |
12920 KB |
Output is correct |
6 |
Correct |
1071 ms |
13000 KB |
Output is correct |
7 |
Correct |
1069 ms |
12920 KB |
Output is correct |
8 |
Correct |
1062 ms |
12988 KB |
Output is correct |
9 |
Correct |
1053 ms |
13048 KB |
Output is correct |
10 |
Correct |
1055 ms |
12928 KB |
Output is correct |
11 |
Correct |
1058 ms |
12968 KB |
Output is correct |
12 |
Correct |
1091 ms |
12920 KB |
Output is correct |
13 |
Correct |
1090 ms |
12836 KB |
Output is correct |
14 |
Correct |
1085 ms |
12924 KB |
Output is correct |
15 |
Correct |
1051 ms |
12896 KB |
Output is correct |
16 |
Correct |
193 ms |
8056 KB |
Output is correct |
17 |
Correct |
207 ms |
8184 KB |
Output is correct |
18 |
Correct |
198 ms |
8056 KB |
Output is correct |
19 |
Correct |
207 ms |
8184 KB |
Output is correct |
20 |
Correct |
203 ms |
8060 KB |
Output is correct |
21 |
Correct |
748 ms |
12476 KB |
Output is correct |
22 |
Correct |
758 ms |
12540 KB |
Output is correct |
23 |
Correct |
737 ms |
12604 KB |
Output is correct |
24 |
Correct |
748 ms |
12540 KB |
Output is correct |
25 |
Correct |
778 ms |
12408 KB |
Output is correct |
26 |
Correct |
960 ms |
12408 KB |
Output is correct |
27 |
Correct |
969 ms |
12408 KB |
Output is correct |
28 |
Correct |
924 ms |
12408 KB |
Output is correct |
29 |
Correct |
930 ms |
12280 KB |
Output is correct |
30 |
Correct |
1030 ms |
12916 KB |
Output is correct |
31 |
Correct |
1036 ms |
13020 KB |
Output is correct |
32 |
Correct |
1038 ms |
12920 KB |
Output is correct |
33 |
Correct |
1050 ms |
12920 KB |
Output is correct |
34 |
Correct |
1062 ms |
12920 KB |
Output is correct |
35 |
Correct |
1042 ms |
12792 KB |
Output is correct |
36 |
Correct |
1044 ms |
12876 KB |
Output is correct |
37 |
Correct |
1061 ms |
12844 KB |
Output is correct |
38 |
Correct |
1052 ms |
12920 KB |
Output is correct |
39 |
Correct |
22 ms |
6016 KB |
Output is correct |
40 |
Correct |
21 ms |
6004 KB |
Output is correct |
41 |
Correct |
22 ms |
6016 KB |
Output is correct |
42 |
Correct |
21 ms |
6016 KB |
Output is correct |
43 |
Correct |
22 ms |
6016 KB |
Output is correct |
44 |
Correct |
23 ms |
6016 KB |
Output is correct |
45 |
Correct |
23 ms |
6016 KB |
Output is correct |
46 |
Correct |
23 ms |
6016 KB |
Output is correct |
47 |
Correct |
24 ms |
6008 KB |
Output is correct |
48 |
Correct |
23 ms |
6016 KB |
Output is correct |
49 |
Correct |
22 ms |
6016 KB |
Output is correct |
50 |
Correct |
27 ms |
6008 KB |
Output is correct |
51 |
Correct |
21 ms |
6016 KB |
Output is correct |
52 |
Correct |
22 ms |
6008 KB |
Output is correct |
53 |
Correct |
22 ms |
6016 KB |
Output is correct |
54 |
Correct |
15 ms |
5632 KB |
Output is correct |
55 |
Correct |
15 ms |
5504 KB |
Output is correct |
56 |
Correct |
15 ms |
5632 KB |
Output is correct |
57 |
Correct |
15 ms |
5504 KB |
Output is correct |
58 |
Correct |
15 ms |
5504 KB |
Output is correct |
59 |
Correct |
1696 ms |
12768 KB |
Output is correct |
60 |
Correct |
1666 ms |
12840 KB |
Output is correct |
61 |
Correct |
1656 ms |
12844 KB |
Output is correct |
62 |
Correct |
1698 ms |
12752 KB |
Output is correct |
63 |
Correct |
1713 ms |
12748 KB |
Output is correct |
64 |
Correct |
1932 ms |
12860 KB |
Output is correct |
65 |
Correct |
1928 ms |
12852 KB |
Output is correct |
66 |
Correct |
1927 ms |
12808 KB |
Output is correct |
67 |
Correct |
1909 ms |
12808 KB |
Output is correct |
68 |
Correct |
1905 ms |
12788 KB |
Output is correct |
69 |
Correct |
1670 ms |
13072 KB |
Output is correct |
70 |
Correct |
1668 ms |
12796 KB |
Output is correct |
71 |
Correct |
1676 ms |
12924 KB |
Output is correct |
72 |
Correct |
1711 ms |
12868 KB |
Output is correct |
73 |
Correct |
1684 ms |
12856 KB |
Output is correct |
74 |
Correct |
243 ms |
8056 KB |
Output is correct |
75 |
Correct |
251 ms |
8184 KB |
Output is correct |
76 |
Correct |
248 ms |
8160 KB |
Output is correct |
77 |
Correct |
250 ms |
8132 KB |
Output is correct |
78 |
Correct |
252 ms |
8056 KB |
Output is correct |