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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#91058 | #6137. Sub-cycle Graph | yyyyxh | WA | 145ms | 9260kb | C++17 | 1.2kb | 2023-03-26 22:19:11 | 2023-03-26 22:19:13 |
Judging History
answer
#include <cstdio>
using namespace std;
template<typename T>
T read(){
char c=getchar();T x=0;
while(c<48||c>57) c=getchar();
do x=(x<<1)+(x<<3)+(c^48),c=getchar();
while(c>=48&&c<=57);
return x;
}
typedef long long ll;
const int P=1000000007;
int qp(int a,int b=P-2){
int res=1;
while(b){
if(b&1) res=(ll)res*a%P;
a=(ll)a*a%P;b>>=1;
}
return res;
}
int fac[1000003],fiv[1000003];
int comb(int a,int b){
if(b<0||b>a) return 0;
return (ll)fac[a]*fiv[b]%P*fiv[a-b]%P;
}
void inc(int &x,int v){if((x+=v)>=P) x-=P;}
void dec(int &x,int v){if((x-=v)<0) x+=P;}
int main(){
int tc=read<int>();
fac[0]=1;
for(int i=1;i<=1000000;++i) fac[i]=(ll)fac[i-1]*i%P;
fiv[1000000]=qp(fac[1000000]);
for(int i=1000000;i;--i) fiv[i-1]=(ll)fiv[i]*i%P;
while(tc--){
int n=read<int>();
ll m=read<ll>();
if(m>n){puts("0");continue;}
if(m==n){printf("%d\n",fac[n-1]);continue;}
m=n-m;
int pw=1,res=0;
for(int i=0;i<=m;++i){
if((m^i)&1) dec(res,(ll)comb(m,i)*pw%P*comb(n-m+i-1,m-1)%P);
else inc(res,(ll)comb(m,i)*pw%P*comb(n-m+i-1,m-1)%P);
inc(pw,pw);
}
res=(ll)res*fiv[m]%P*fac[n]%P*qp((P+1)>>1,m)%P;
printf("%d\n",res);
}
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 9260kb
input:
3 4 2 4 3 5 3
output:
15 12 90
result:
ok 3 number(s): "15 12 90"
Test #2:
score: -100
Wrong Answer
time: 145ms
memory: 9240kb
input:
17446 3 0 3 1 3 2 3 3 4 0 4 1 4 2 4 3 4 4 5 0 5 1 5 2 5 3 5 4 5 5 6 0 6 1 6 2 6 3 6 4 6 5 6 6 7 0 7 1 7 2 7 3 7 4 7 5 7 6 7 7 8 0 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 9 0 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 9 9 10 0 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 11 0 11 1 11 2 11 3 11 4 11 5 11 6 11 7 11...
output:
1 3 3 2 1 6 15 12 6 1 10 45 90 60 24 1 15 105 375 630 360 120 1 21 210 1155 3465 5040 2520 720 1 28 378 2940 13545 35280 45360 20160 5040 1 36 630 6552 42525 170100 393120 453600 181440 40320 1 45 990 13230 114345 643545 2286900 4762800 4989600 1814400 362880 1 55 1485 24750 273735 2047815 10239075 ...
result:
wrong answer 4th numbers differ - expected: '1', found: '2'