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QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #375668 | #5532. Kangaroo | sichengzhou | 100 ✓ | 26ms | 26568kb | C++14 | 2.8kb | 2024-04-03 14:44:04 | 2024-04-03 14:44:06 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=2020,mod=1e9+7;
int n,cs,cf;
LL f[N][N];
int main()
{
scanf("%d%d%d",&n,&cs,&cf);
f[0][0]=1;
for(int i=0;i<n;i++)
{
for(int j=0;j<=i;j++)
{
if(i+1==cs)
{
if(cf<=i)
{
if(j>=2)
{
f[i+1][j]+=f[i][j]*(j-1)%mod;
f[i+1][j]%=mod;
}else if(j==1&&i==n-1)
{
f[i+1][j]+=f[i][j]*j%mod;
f[i+1][j]%=mod;
}
}else{
if(j>=1)
{
f[i+1][j]+=f[i][j]*j%mod;
f[i+1][j]%=mod;
}
}
}else if(i+1==cf)
{
if(cs<=i)
{
if(j>=2)
{
f[i+1][j]+=f[i][j]*(j-1)%mod;
f[i+1][j]%=mod;
}else if(j==1&&i==n-1)
{
f[i+1][j]+=f[i][j]*j%mod;
f[i+1][j]%=mod;
}
}else{
if(j>=1)
{
f[i+1][j]+=f[i][j]*j%mod;
f[i+1][j]%=mod;
}
}
}else{
if(i<cs&&i<cf)
{
if(j>=2)
{
f[i+1][j-1]+=j*(j-1)%mod*f[i][j]%mod;
f[i+1][j-1]%=mod;
}
}else if(cs<=i&&cf<=i)
{
if(j>=3)
{
f[i+1][j-1]+=((j-1)*(j-1)-(j-2)-1)%mod*f[i][j]%mod;
f[i+1][j-1]%=mod;
}else if(j==2&&i==n-1)
{
f[i+1][j-1]+=f[i][j]%mod;
f[i+1][j-1]%=mod;
}
}else if(cs<=i)
{
if(j>=2)
{
f[i+1][j-1]+=(j*(j-1)-(j-1))%mod*f[i][j]%mod;
f[i+1][j-1]%=mod;
}
}else{
if(j>=2)
{
f[i+1][j-1]+=(j*(j-1)-(j-1))%mod*f[i][j]%mod;
f[i+1][j-1]%=mod;
}
}
}
f[i+1][j+1]+=f[i][j];
f[i+1][j+1]%=mod;
}
}
printf("%lld\n",f[n][1]);
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Subtask #1:
score: 6
Accepted
Test #1:
score: 6
Accepted
time: 0ms
memory: 3772kb
input:
7 3 6
output:
14
result:
ok 1 number(s): "14"
Subtask #2:
score: 30
Accepted
Dependency #1:
100%
Accepted
Test #2:
score: 30
Accepted
time: 1ms
memory: 3964kb
input:
39 36 32
output:
964903316
result:
ok 1 number(s): "964903316"
Test #3:
score: 0
Accepted
time: 1ms
memory: 3920kb
input:
26 1 26
output:
955348527
result:
ok 1 number(s): "955348527"
Test #4:
score: 0
Accepted
time: 1ms
memory: 4076kb
input:
40 11 33
output:
695661890
result:
ok 1 number(s): "695661890"
Test #5:
score: 0
Accepted
time: 1ms
memory: 4024kb
input:
39 39 38
output:
717149364
result:
ok 1 number(s): "717149364"
Test #6:
score: 0
Accepted
time: 1ms
memory: 3916kb
input:
40 10 25
output:
912929610
result:
ok 1 number(s): "912929610"
Test #7:
score: 0
Accepted
time: 1ms
memory: 3972kb
input:
37 25 23
output:
250748685
result:
ok 1 number(s): "250748685"
Test #8:
score: 0
Accepted
time: 1ms
memory: 3964kb
input:
39 2 38
output:
624060592
result:
ok 1 number(s): "624060592"
Test #9:
score: 0
Accepted
time: 1ms
memory: 3920kb
input:
40 18 22
output:
739993796
result:
ok 1 number(s): "739993796"
Test #10:
score: 0
Accepted
time: 1ms
memory: 4028kb
input:
40 11 35
output:
135213497
result:
ok 1 number(s): "135213497"
Subtask #3:
score: 15
Accepted
Dependency #1:
100%
Accepted
Dependency #2:
100%
Accepted
Test #11:
score: 15
Accepted
time: 0ms
memory: 4736kb
input:
199 100 70
output:
914653136
result:
ok 1 number(s): "914653136"
Test #12:
score: 0
Accepted
time: 1ms
memory: 4648kb
input:
187 3 40
output:
928785584
result:
ok 1 number(s): "928785584"
Test #13:
score: 0
Accepted
time: 0ms
memory: 4844kb
input:
199 198 197
output:
38412688
result:
ok 1 number(s): "38412688"
Test #14:
score: 0
Accepted
time: 1ms
memory: 4836kb
input:
200 40 140
output:
367088143
result:
ok 1 number(s): "367088143"
Test #15:
score: 0
Accepted
time: 1ms
memory: 4888kb
input:
199 111 3
output:
870834793
result:
ok 1 number(s): "870834793"
Test #16:
score: 0
Accepted
time: 1ms
memory: 4752kb
input:
200 133 73
output:
343127012
result:
ok 1 number(s): "343127012"
Test #17:
score: 0
Accepted
time: 1ms
memory: 4656kb
input:
178 15 163
output:
160852284
result:
ok 1 number(s): "160852284"
Test #18:
score: 0
Accepted
time: 1ms
memory: 4740kb
input:
197 43 79
output:
332057544
result:
ok 1 number(s): "332057544"
Test #19:
score: 0
Accepted
time: 1ms
memory: 4704kb
input:
200 33 79
output:
742545318
result:
ok 1 number(s): "742545318"
Subtask #4:
score: 49
Accepted
Dependency #1:
100%
Accepted
Dependency #2:
100%
Accepted
Dependency #3:
100%
Accepted
Test #20:
score: 49
Accepted
time: 5ms
memory: 8132kb
input:
658 169 438
output:
206087110
result:
ok 1 number(s): "206087110"
Test #21:
score: 0
Accepted
time: 5ms
memory: 8472kb
input:
700 207 509
output:
478311263
result:
ok 1 number(s): "478311263"
Test #22:
score: 0
Accepted
time: 6ms
memory: 9036kb
input:
755 139 507
output:
103783948
result:
ok 1 number(s): "103783948"
Test #23:
score: 0
Accepted
time: 26ms
memory: 26568kb
input:
2000 500 1500
output:
123410309
result:
ok 1 number(s): "123410309"
Test #24:
score: 0
Accepted
time: 21ms
memory: 26524kb
input:
2000 1000 1001
output:
956197482
result:
ok 1 number(s): "956197482"
Test #25:
score: 0
Accepted
time: 19ms
memory: 26564kb
input:
2000 666 1333
output:
993781645
result:
ok 1 number(s): "993781645"
Test #26:
score: 0
Accepted
time: 19ms
memory: 26392kb
input:
1991 198 677
output:
155058730
result:
ok 1 number(s): "155058730"
Test #27:
score: 0
Accepted
time: 7ms
memory: 18532kb
input:
1498 299 659
output:
665757882
result:
ok 1 number(s): "665757882"