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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#476488 | #2568. Mountains | weiguoliang | WA | 0ms | 3708kb | C++14 | 1.4kb | 2024-07-13 19:49:46 | 2024-07-13 19:49:47 |
Judging History
answer
#include<bits/stdc++.h>
#define ll long long
#define N 105
#define mod 1000000007
using namespace std;
ll n,m,k,a[N][N],jie[N<<2],inv[N<<2];
ll qpow(ll a,ll b){ll ans=1;
while(b){
if(b&1)ans=ans*a%mod;
a=a*a%mod;
b>>=1;
}
return ans;
}
ll sh(ll n){ll i,k,j,l,ans=1;
for(i=1;i<=n;i++){
for(k=i+1;k<=n;k++)if(a[k][i])swap(a[k],a[i]),ans=-ans;
if(!a[i][i])return 0;
for(k=i+1;k<=n;k++){
while(a[k][i]){
if(!a[i][i]){
if(a[k][i]){
swap(a[i],a[k]),ans=-ans;
break;
}
else return 0;
}
l=a[k][i]/a[i][i];
for(j=1;j<=n;j++)a[k][j]=(a[k][j]-a[i][j]*l%mod+mod)%mod;
swap(a[k],a[i]),ans=-ans;
}
}
}
if(ans==-1)ans=(ans+mod)%mod;
for(i=1;i<=n;i++)ans=ans*a[i][i]%mod;
return ans;
}
ll c(ll n,ll m){
if(n>m||n<0)return 0;
return jie[m]*inv[m-n]%mod*inv[n]%mod;
}
int main(){ll i,j;
ios::sync_with_stdio(0);
cin.tie(0),cout.tie(0);
cin>>n>>m>>k;
jie[0]=1;
for(i=1;i<=(n<<2);i++)jie[i]=jie[i-1]*i%mod;
inv[n<<2]=qpow(jie[n<<2],mod-2);
for(i=(n<<2)-1;i>=0;i--)inv[i]=inv[i+1]*(i+1)%mod;
for(i=1;i<=k;i++){
for(j=1;j<=k;j++){
a[i][j]=c(m+i-j,m+n);
}
}
cout<<sh(k);
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 3708kb
input:
1 1 1
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3584kb
input:
2 2 2
output:
20
result:
ok 1 number(s): "20"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3704kb
input:
2 3 4
output:
490
result:
ok 1 number(s): "490"
Test #4:
score: 0
Accepted
time: 0ms
memory: 3652kb
input:
1 2 8
output:
45
result:
ok 1 number(s): "45"
Test #5:
score: -100
Wrong Answer
time: 0ms
memory: 3524kb
input:
1 10 2
output:
0
result:
wrong answer 1st numbers differ - expected: '66', found: '0'