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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#526421 | #8211. Enumerating Substrings | ucup-team3792 | AC ✓ | 32ms | 23284kb | C++14 | 1.4kb | 2024-08-21 15:37:48 | 2024-08-21 15:37:49 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
const int mod=1e9+7;
int n,m,k,f[2005],g[2005],ans,pw[2005],ipw[2005],pwk[1000005];
int fac[2005],inv[2005],dn[2005][2005];
int qpow(int a,int b)
{
if(b==0) return 1;
int g=qpow(a,b/2);
g=1ll*g*g%mod;
if(b&1) g=1ll*g*a%mod;
return g;
}
int calc(int x)
{
if(x>n) return 0;
return 1ll*(n-x+1)*pwk[n-x]%mod;
}
int C(int n,int m)
{
if(n<m) return 0;
return 1ll*dn[k-n+1][m]*inv[m]%mod;
}
int main()
{
cin>>n>>m>>k;
fac[0]=inv[0]=pw[0]=ipw[0]=pwk[0]=1;
for(int i=1;i<=m;i++)
{
fac[i]=1ll*fac[i-1]*i%mod;
inv[i]=qpow(fac[i],mod-2);
pw[i]=1ll*pw[i-1]*2%mod;
ipw[i]=qpow(pw[i],mod-2);
}
for(int i=1;i<=n;i++)
{
pwk[i]=1ll*pwk[i-1]*k%mod;
}
for(int i=1;i<=m;i++)
{
dn[i][0]=1;
dn[i][1]=(k-i+1);
for(int j=1;j<=m;j++)
{
dn[i][j+1]=1ll*dn[i][j]*(k-i+1-j)%mod;
}
}
for(int i=0;i*2<=m;i++)
{
if(i==0) g[i]=calc(m);
else
{
int c=1;
for(int j=m;j<=n;j+=m-i)
{
g[i]+=1ll*c*calc(j)%mod;
if(g[i]>=mod) g[i]-=mod;
c=mod-c;
}
}
int w=1ll*C(k,i)*fac[i]%mod,sum=0;
for(int j=0;i*2+j*2<=m;j++)
{
sum+=1ll*C(k-i,j)*C(k-i-j,m-i*2-j*2)%mod*fac[m-i*2]%mod*ipw[j]%mod;
if(sum>=mod) sum-=mod;
}
f[i]=1ll*w*sum%mod;
}
for(int i=1;i*2<=m;i++)
{
f[0]-=f[i];
if(f[0]<0) f[0]+=mod;
}
for(int i=0;i*2<=m;i++)
{
ans+=1ll*f[i]*g[i]%mod;
if(ans>=mod) ans-=mod;
}
cout<<ans;
}
这程序好像有点Bug,我给组数据试试?
Details
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Test #1:
score: 100
Accepted
time: 1ms
memory: 5676kb
input:
4 2 3
output:
228
result:
ok 1 number(s): "228"
Test #2:
score: 0
Accepted
time: 32ms
memory: 23284kb
input:
999999 1999 12345678
output:
52352722
result:
ok 1 number(s): "52352722"
Test #3:
score: 0
Accepted
time: 0ms
memory: 5780kb
input:
7 4 2
output:
182
result:
ok 1 number(s): "182"
Test #4:
score: 0
Accepted
time: 0ms
memory: 5768kb
input:
4 3 4
output:
480
result:
ok 1 number(s): "480"
Test #5:
score: 0
Accepted
time: 0ms
memory: 5724kb
input:
3 1 1
output:
3
result:
ok 1 number(s): "3"
Test #6:
score: 0
Accepted
time: 1ms
memory: 5584kb
input:
5 5 1
output:
0
result:
ok 1 number(s): "0"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5700kb
input:
7 4 3
output:
5784
result:
ok 1 number(s): "5784"
Test #8:
score: 0
Accepted
time: 0ms
memory: 5764kb
input:
5 2 4
output:
3932
result:
ok 1 number(s): "3932"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5680kb
input:
8 2 2
output:
1522
result:
ok 1 number(s): "1522"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5768kb
input:
8 1 2
output:
2048
result:
ok 1 number(s): "2048"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5592kb
input:
7 5 3
output:
2430
result:
ok 1 number(s): "2430"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5584kb
input:
10 4 3
output:
272004
result:
ok 1 number(s): "272004"
Test #13:
score: 0
Accepted
time: 10ms
memory: 13552kb
input:
675978 614 2
output:
0
result:
ok 1 number(s): "0"
Test #14:
score: 0
Accepted
time: 2ms
memory: 5832kb
input:
244613 38 1
output:
0
result:
ok 1 number(s): "0"
Test #15:
score: 0
Accepted
time: 14ms
memory: 19840kb
input:
186293 1462 1
output:
0
result:
ok 1 number(s): "0"
Test #16:
score: 0
Accepted
time: 5ms
memory: 14488kb
input:
24867 886 1
output:
0
result:
ok 1 number(s): "0"
Test #17:
score: 0
Accepted
time: 16ms
memory: 17132kb
input:
976164 1014 2
output:
0
result:
ok 1 number(s): "0"
Test #18:
score: 0
Accepted
time: 2ms
memory: 7672kb
input:
179356 2 716844809
output:
577866092
result:
ok 1 number(s): "577866092"
Test #19:
score: 0
Accepted
time: 7ms
memory: 9932kb
input:
621001 130 310625363
output:
892869197
result:
ok 1 number(s): "892869197"
Test #20:
score: 0
Accepted
time: 9ms
memory: 16144kb
input:
678862 850 754662812
output:
582264789
result:
ok 1 number(s): "582264789"
Test #21:
score: 0
Accepted
time: 13ms
memory: 17796kb
input:
650845 978 348443366
output:
825425732
result:
ok 1 number(s): "825425732"
Test #22:
score: 0
Accepted
time: 0ms
memory: 12532kb
input:
669914 402 87448112
output:
318098088
result:
ok 1 number(s): "318098088"
Test #23:
score: 0
Accepted
time: 6ms
memory: 14660kb
input:
998593 530 681228665
output:
408255654
result:
ok 1 number(s): "408255654"
Test #24:
score: 0
Accepted
time: 27ms
memory: 21316kb
input:
369361 1954 125266115
output:
509912384
result:
ok 1 number(s): "509912384"
Test #25:
score: 0
Accepted
time: 21ms
memory: 20848kb
input:
900226 1378 424079373
output:
406320917
result:
ok 1 number(s): "406320917"
Test #26:
score: 0
Accepted
time: 17ms
memory: 20280kb
input:
334887 1506 17859926
output:
503264679
result:
ok 1 number(s): "503264679"
Test #27:
score: 0
Accepted
time: 8ms
memory: 12844kb
input:
936048 544 53978328
output:
548647866
result:
ok 1 number(s): "548647866"
Test #28:
score: 0
Accepted
time: 12ms
memory: 16288kb
input:
152789 1264 792983073
output:
839541707
result:
ok 1 number(s): "839541707"
Test #29:
score: 0
Accepted
time: 15ms
memory: 20348kb
input:
714493 1392 91796331
output:
721071046
result:
ok 1 number(s): "721071046"
Test #30:
score: 0
Accepted
time: 8ms
memory: 15596kb
input:
269571 816 830801077
output:
330064211
result:
ok 1 number(s): "330064211"
Test #31:
score: 0
Accepted
time: 14ms
memory: 16492kb
input:
845120 944 424581630
output:
348960190
result:
ok 1 number(s): "348960190"
Test #32:
score: 0
Accepted
time: 7ms
memory: 11148kb
input:
533990 368 163586376
output:
522092095
result:
ok 1 number(s): "522092095"
Test #33:
score: 0
Accepted
time: 22ms
memory: 21024kb
input:
181707 1792 462399634
output:
373795106
result:
ok 1 number(s): "373795106"
Test #34:
score: 0
Accepted
time: 26ms
memory: 21020kb
input:
417349 1920 761212891
output:
587051329
result:
ok 1 number(s): "587051329"
Test #35:
score: 0
Accepted
time: 17ms
memory: 20036kb
input:
526583 1344 500217637
output:
108767800
result:
ok 1 number(s): "108767800"
Test #36:
score: 0
Accepted
time: 14ms
memory: 14352kb
input:
867054 769 93998191
output:
239123369
result:
ok 1 number(s): "239123369"
Extra Test:
score: 0
Extra Test Passed