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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 |
---|---|---|---|---|---|---|---|---|---|
#474159 | #2568. Mountains | yqh2025 | WA | 0ms | 4136kb | C++14 | 1.5kb | 2024-07-12 16:25:39 | 2024-07-12 16:25:40 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=110,mod=1e9+7;
int ksm(int x,int y){int ans=1;while(y){if(y&1)ans=ans*x%mod;x=x*x%mod;y>>=1;}return ans;}
int inv(int x){return ksm(x,mod-2);}
struct matrix{
int s[N][N],n,m;
int* operator [](int x){return s[x];}
matrix(){memset(s,0,sizeof(s));n=m=0;}
};
int dat(matrix x){
int n=x.n,fl=1;
for(int i=1;i<=n;i++){
if(!x[i][i]){
for(int j=i+1;j<=n;j++){
if(x[j][i]){
fl*=-1;for(int k=1;k<=n;k++)swap(x[i][k],x[j][k]);
break;
}
}
}
if(!x[i][i])return 0;
for(int j=i+1;j<=n;j++){
if(x[j][i]>x[i][i]){
fl*=-1;for(int k=1;k<=n;k++)swap(x[i][k],x[j][k]);
}
while(x[j][i]){
int S=x[i][i]/x[j][i];
for(int k=i;k<=n;k++)x[i][k]=(x[i][k]-S*x[j][k]);
fl*=-1;for(int k=1;k<=n;k++)swap(x[i][k],x[j][k]);
}
// for(int k=1;k<=n;k++)x[j][k]%=mod;
}
}
int ans=(fl+mod)%mod;
for(int i=1;i<=n;i++)ans=ans*(x[i][i]+mod)%mod;
return ans;
}
int n,m,k;
int jc[N<<1],invjc[N<<1];
void init(){
int u=n+m;
jc[0]=1;for(int i=1;i<=u;i++)jc[i]=jc[i-1]*i%mod;
invjc[u]=inv(jc[u]);
for(int i=u-1;i>=0;i--)invjc[i]=invjc[i+1]*(i+1)%mod;
}
int C(int n,int m){
if(n<m)return 0;
return jc[n]*invjc[m]%mod*invjc[n-m]%mod;
}
signed main(){
scanf("%lld%lld%lld",&n,&m,&k);
init();
matrix A;A.n=A.m=k;
for(int i=1;i<=k;i++){
for(int j=1;j<=k;j++){
int x=n+(j-i),y=m-(j-i);
A[i][j]=C(x+y,x);
}
}
printf("%lld",dat(A));
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 4060kb
input:
1 1 1
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 0ms
memory: 4060kb
input:
2 2 2
output:
20
result:
ok 1 number(s): "20"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3940kb
input:
2 3 4
output:
490
result:
ok 1 number(s): "490"
Test #4:
score: 0
Accepted
time: 0ms
memory: 4056kb
input:
1 2 8
output:
45
result:
ok 1 number(s): "45"
Test #5:
score: 0
Accepted
time: 0ms
memory: 4060kb
input:
1 10 2
output:
66
result:
ok 1 number(s): "66"
Test #6:
score: 0
Accepted
time: 0ms
memory: 4132kb
input:
9 5 7
output:
371850968
result:
ok 1 number(s): "371850968"
Test #7:
score: 0
Accepted
time: 0ms
memory: 3936kb
input:
3 3 1
output:
20
result:
ok 1 number(s): "20"
Test #8:
score: -100
Wrong Answer
time: 0ms
memory: 4136kb
input:
7 7 9
output:
580093176
result:
wrong answer 1st numbers differ - expected: '166345303', found: '580093176'