QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#474416 | #2568. Mountains | lichenyu_ac | WA | 11ms | 21044kb | C++14 | 1.4kb | 2024-07-12 17:57:06 | 2024-07-12 17:57:06 |
Judging History
answer
#include<bits/stdc++.h>
#define ing long long
typedef long long ll;
using namespace std;
const int N=510,M=1e6+10,mod=1e9+7;
ll power(ll a,ll b){
ll ans=1;
for(;b;b>>=1){
if(b&1)ans=ans*a%mod;
a=a*a%mod;
}
return ans;
}
ll n,m,K;
ll A[N][N],f[M],incf[M];
void init(int len){
f[0]=1;
for(int i=1;i<=len;i++)f[i]=f[i-1]*i%mod;
incf[len]=power(f[len],mod-2);
for(int i=len-1;i>=0;i--)incf[i]=incf[i+1]*(i+1)%mod;
}
ll C(ll a,ll b){
if(a<b)return 0;
return f[a]*incf[b]%mod*incf[a-b]%mod;
}
ll Guess(){
ll ans=1;
for(int i=1;i<=K;i++){
if(!A[i][i]){
for(int j=i+1;j<=K;j++){
if(A[j][i]){
ans*=-1;
for(int k=1;k<=n;k++)
swap(A[i][k],A[j][k]);
break;
}
}
}
if(!A[i][i])return 0;
for(int j=i+1;j<=K;j++){
if(A[j][i]>A[i][i]){
ans*=-1;
for(int k=1;k<=K;k++)
swap(A[i][k],A[j][k]);
}
while(A[j][i]){
ll tmp=A[i][i]*power(A[j][i],mod-2)%mod;
for(int k=1;k<=K;k++)
A[i][k]=(A[i][k]-tmp*A[j][k]%mod+mod)%mod;
ans*=-1;
for(int k=1;k<=K;k++)
swap(A[i][k],A[j][k]);
}
for(int k=1;k<=K;k++)A[j][k]%=mod;
}
}
ans=(ans+mod)%mod;
for(int i=1;i<=K;i++)ans=(ans*A[i][i]%mod+mod)%mod;
return ans;
}
signed main(){
init(M-1);
scanf("%lld%lld%lld",&n,&m,&K);
for(int i=1;i<=K;i++)
for(int j=1;j<=K;j++){
ll x=n+(j-i),y=m-(j-i);
A[i][j]=C(x+y,x);
}
printf("%lld\n",Guess());
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 11ms
memory: 19508kb
input:
1 1 1
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 0ms
memory: 20588kb
input:
2 2 2
output:
20
result:
ok 1 number(s): "20"
Test #3:
score: 0
Accepted
time: 11ms
memory: 19864kb
input:
2 3 4
output:
490
result:
ok 1 number(s): "490"
Test #4:
score: 0
Accepted
time: 3ms
memory: 21028kb
input:
1 2 8
output:
45
result:
ok 1 number(s): "45"
Test #5:
score: 0
Accepted
time: 11ms
memory: 21044kb
input:
1 10 2
output:
66
result:
ok 1 number(s): "66"
Test #6:
score: 0
Accepted
time: 3ms
memory: 20700kb
input:
9 5 7
output:
371850968
result:
ok 1 number(s): "371850968"
Test #7:
score: 0
Accepted
time: 11ms
memory: 19908kb
input:
3 3 1
output:
20
result:
ok 1 number(s): "20"
Test #8:
score: 0
Accepted
time: 11ms
memory: 19884kb
input:
7 7 9
output:
166345303
result:
ok 1 number(s): "166345303"
Test #9:
score: 0
Accepted
time: 11ms
memory: 20788kb
input:
25 15 25
output:
850087558
result:
ok 1 number(s): "850087558"
Test #10:
score: -100
Wrong Answer
time: 9ms
memory: 19864kb
input:
45 59 71
output:
793769136
result:
wrong answer 1st numbers differ - expected: '659153227', found: '793769136'