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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#403982 | #8211. Enumerating Substrings | i_am_noob# | AC ✓ | 11ms | 9588kb | C++14 | 2.0kb | 2024-05-03 01:29:33 | 2024-05-03 01:29:33 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
using ll=long long;
using pii=pair<int,int>;
#define pb push_back
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())
const int N=2005,M=1000005,mod=1000000007;
int add(int x, int y){x+=y; if(x>=mod) x-=mod; return x;}
int sub(int x, int y){x-=y; if(x<0) x+=mod; return x;}
int mul(int x, int y){return 1ll*x*y%mod;}
int Pow(int x, ll y=mod-2){int res=1; for(; y; y>>=1,x=mul(x,x)) if(y&1) res=mul(res,x); return res;}
int n,m,k,pw[M],dp[N][N],fac[N],inv[N],ifac[N],kval[N],inv2[N];
signed main(){
ios_base::sync_with_stdio(0),cin.tie(0);
fac[0]=inv[1]=ifac[0]=1;
for(int i=1; i<N; ++i) fac[i]=mul(fac[i-1],i);
for(int i=2; i<N; ++i) inv[i]=mul(inv[mod%i],mod-mod/i);
for(int i=1; i<N; ++i) ifac[i]=mul(ifac[i-1],inv[i]);
inv2[0]=1,inv2[1]=Pow(2);
for(int i=2; i<N; ++i) inv2[i]=mul(inv2[i-1],inv2[1]);
cin >> n >> m >> k;
pw[0]=1;
for(int i=1; i<M; ++i) pw[i]=mul(pw[i-1],k);
kval[0]=1;
for(int i=1; i<N; ++i) kval[i]=mul(kval[i-1],k+1-i);
int tot=0;
for(int i=0; i*2<=m; ++i){
int tmp=mul(mul(kval[m-i],fac[m]),mul(ifac[i],ifac[m-i*2]));
tmp=mul(tmp,inv2[i]);
tot=add(tot,tmp);
//cout << tot << "\n";
}
int res=0;
for(int x=1; x*2<=m; ++x){
int de=0;
for(int i=x; i*2<=m; ++i){
int tmp=mul(mul(kval[m-i],fac[m-x*2]),mul(ifac[i-x],ifac[m-i*2]));
//tmp=mul(mul(tmp,fac[i]),mul(ifac[i-x],ifac[x]));
tmp=mul(tmp,inv2[i-x]);
de=add(de,tmp);
}
//cout << x << ' ' << de << "\n";
tot=sub(tot,de);
for(int i=1; (i-1)*(m-x)+m<=n; ++i){
if(i&1) res=add(res,mul(de,mul(pw[n-((i-1)*(m-x)+m)],n-((i-1)*(m-x)+m)+1)));
else res=sub(res,mul(de,mul(pw[n-((i-1)*(m-x)+m)],n-((i-1)*(m-x)+m)+1)));
}
}
res=add(res,mul(tot,mul(pw[n-m],n-m+1)));
cout << res << "\n";
}
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: 6ms
memory: 9588kb
input:
4 2 3
output:
228
result:
ok 1 number(s): "228"
Test #2:
score: 0
Accepted
time: 10ms
memory: 7916kb
input:
999999 1999 12345678
output:
52352722
result:
ok 1 number(s): "52352722"
Test #3:
score: 0
Accepted
time: 5ms
memory: 7792kb
input:
7 4 2
output:
182
result:
ok 1 number(s): "182"
Test #4:
score: 0
Accepted
time: 3ms
memory: 8824kb
input:
4 3 4
output:
480
result:
ok 1 number(s): "480"
Test #5:
score: 0
Accepted
time: 5ms
memory: 7852kb
input:
3 1 1
output:
3
result:
ok 1 number(s): "3"
Test #6:
score: 0
Accepted
time: 3ms
memory: 8956kb
input:
5 5 1
output:
0
result:
ok 1 number(s): "0"
Test #7:
score: 0
Accepted
time: 2ms
memory: 7876kb
input:
7 4 3
output:
5784
result:
ok 1 number(s): "5784"
Test #8:
score: 0
Accepted
time: 6ms
memory: 8140kb
input:
5 2 4
output:
3932
result:
ok 1 number(s): "3932"
Test #9:
score: 0
Accepted
time: 5ms
memory: 7900kb
input:
8 2 2
output:
1522
result:
ok 1 number(s): "1522"
Test #10:
score: 0
Accepted
time: 5ms
memory: 8472kb
input:
8 1 2
output:
2048
result:
ok 1 number(s): "2048"
Test #11:
score: 0
Accepted
time: 3ms
memory: 8992kb
input:
7 5 3
output:
2430
result:
ok 1 number(s): "2430"
Test #12:
score: 0
Accepted
time: 5ms
memory: 8044kb
input:
10 4 3
output:
272004
result:
ok 1 number(s): "272004"
Test #13:
score: 0
Accepted
time: 10ms
memory: 7652kb
input:
675978 614 2
output:
0
result:
ok 1 number(s): "0"
Test #14:
score: 0
Accepted
time: 7ms
memory: 9268kb
input:
244613 38 1
output:
0
result:
ok 1 number(s): "0"
Test #15:
score: 0
Accepted
time: 3ms
memory: 8656kb
input:
186293 1462 1
output:
0
result:
ok 1 number(s): "0"
Test #16:
score: 0
Accepted
time: 6ms
memory: 8380kb
input:
24867 886 1
output:
0
result:
ok 1 number(s): "0"
Test #17:
score: 0
Accepted
time: 11ms
memory: 8292kb
input:
976164 1014 2
output:
0
result:
ok 1 number(s): "0"
Test #18:
score: 0
Accepted
time: 6ms
memory: 8552kb
input:
179356 2 716844809
output:
577866092
result:
ok 1 number(s): "577866092"
Test #19:
score: 0
Accepted
time: 9ms
memory: 9256kb
input:
621001 130 310625363
output:
892869197
result:
ok 1 number(s): "892869197"
Test #20:
score: 0
Accepted
time: 9ms
memory: 7860kb
input:
678862 850 754662812
output:
582264789
result:
ok 1 number(s): "582264789"
Test #21:
score: 0
Accepted
time: 9ms
memory: 7860kb
input:
650845 978 348443366
output:
825425732
result:
ok 1 number(s): "825425732"
Test #22:
score: 0
Accepted
time: 4ms
memory: 8396kb
input:
669914 402 87448112
output:
318098088
result:
ok 1 number(s): "318098088"
Test #23:
score: 0
Accepted
time: 10ms
memory: 8132kb
input:
998593 530 681228665
output:
408255654
result:
ok 1 number(s): "408255654"
Test #24:
score: 0
Accepted
time: 6ms
memory: 8112kb
input:
369361 1954 125266115
output:
509912384
result:
ok 1 number(s): "509912384"
Test #25:
score: 0
Accepted
time: 7ms
memory: 8604kb
input:
900226 1378 424079373
output:
406320917
result:
ok 1 number(s): "406320917"
Test #26:
score: 0
Accepted
time: 8ms
memory: 7844kb
input:
334887 1506 17859926
output:
503264679
result:
ok 1 number(s): "503264679"
Test #27:
score: 0
Accepted
time: 11ms
memory: 8404kb
input:
936048 544 53978328
output:
548647866
result:
ok 1 number(s): "548647866"
Test #28:
score: 0
Accepted
time: 7ms
memory: 7816kb
input:
152789 1264 792983073
output:
839541707
result:
ok 1 number(s): "839541707"
Test #29:
score: 0
Accepted
time: 11ms
memory: 9356kb
input:
714493 1392 91796331
output:
721071046
result:
ok 1 number(s): "721071046"
Test #30:
score: 0
Accepted
time: 7ms
memory: 9540kb
input:
269571 816 830801077
output:
330064211
result:
ok 1 number(s): "330064211"
Test #31:
score: 0
Accepted
time: 10ms
memory: 9120kb
input:
845120 944 424581630
output:
348960190
result:
ok 1 number(s): "348960190"
Test #32:
score: 0
Accepted
time: 8ms
memory: 8164kb
input:
533990 368 163586376
output:
522092095
result:
ok 1 number(s): "522092095"
Test #33:
score: 0
Accepted
time: 8ms
memory: 7952kb
input:
181707 1792 462399634
output:
373795106
result:
ok 1 number(s): "373795106"
Test #34:
score: 0
Accepted
time: 10ms
memory: 8820kb
input:
417349 1920 761212891
output:
587051329
result:
ok 1 number(s): "587051329"
Test #35:
score: 0
Accepted
time: 9ms
memory: 9316kb
input:
526583 1344 500217637
output:
108767800
result:
ok 1 number(s): "108767800"
Test #36:
score: 0
Accepted
time: 7ms
memory: 8788kb
input:
867054 769 93998191
output:
239123369
result:
ok 1 number(s): "239123369"
Extra Test:
score: 0
Extra Test Passed