QOJ.ac
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 |
---|---|---|---|---|---|---|---|---|---|
#474521 | #2568. Mountains | XiaoZi_qwq | AC ✓ | 1ms | 10036kb | C++14 | 1.9kb | 2024-07-12 19:41:16 | 2024-07-12 19:41:16 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
inline int read(){
register int x=0;
char c=getchar();
while(c<'0' || '9'<c) c=getchar();
while('0'<=c && c<='9') x=(x<<3)+(x<<1)+c-'0',c=getchar();
return x;
}
const int N=110,Mmax=1000100;
int inv[Mmax<<1],fac[Mmax<<1],inv_fac[Mmax<<1],tot=1;
const int mod=1000000007;
int T,n,m,M[N][N],a[N],b[N],cnt;
inline int qpow(int base,int pow){
int ans=1;
while(pow){
if(pow&1)
ans=1ll*ans*base%mod;
base=1ll*base*base%mod;
pow>>=1;
}
return ans;
}
inline int C(int a,int b){return 1ll*fac[a]*inv_fac[a-b]%mod*inv_fac[b]%mod;}
int det(){
int res=1;
bool flag=false;//正负性
for(int i=1;i<=cnt;i++){
int x=i;
while(x<=cnt && !M[x][i]) x++;
if(x>cnt) return 0;
if(x!=i){
for(int j=i;j<=cnt;j++)
swap(M[x][j],M[i][j]);
flag^=1;
}
res=1ll*res*(M[i][i]+mod)%mod;
int t=qpow(M[i][i],mod-2);
for(int k=i+1;k<=cnt;k++){
int t0=1ll*M[k][i]*t%mod;
for(int j=i;j<=cnt;j++)
M[k][j]=(M[k][j]-1ll*M[i][j]*t0)%mod;
}
}
return flag?mod-res:res;
}
void slove(){
scanf("%d%d%d",&n,&m,&cnt);n++,m++;
while(tot<2*(m+n)){//计算组合数 的预处理
//原理 C(n,m)=n!/(n-m)!/m!
//fac[i]=i!%mod inv_fac[i]=i!%mod的逆元
//C(n,m)=fac[n]*inv_fac[n-m]*inv_fac[m]
tot++;
fac[tot]=1ll*fac[tot-1]*tot%mod;
inv[tot]=1ll*(mod-mod/tot)*inv[mod%tot]%mod;
inv_fac[tot]=1ll*inv_fac[tot-1]*inv[tot]%mod;
}
//for(int i=1;i<=m;i++) scanf("%d %d",a+i,b+i);
for(int i=1;i<=cnt;i++)//(i,m+i-1) 起点
for(int j=1;j<=cnt;j++)//(n+j-1,j) 终点
M[i][j]=(i<=n+j-1 && m+i-1>=j)?C(n+m-2,m+i-1-j):0;
printf("%d\n",det());
}
int main()
{
//freopen("test.in","r",stdin);
//scanf("%d",&T);
fac[0]=inv_fac[0]=1;
fac[1]=inv_fac[1]=inv[1]=1;
slove();
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 7908kb
input:
1 1 1
output:
2
result:
ok 1 number(s): "2"
Test #2:
score: 0
Accepted
time: 0ms
memory: 7908kb
input:
2 2 2
output:
20
result:
ok 1 number(s): "20"
Test #3:
score: 0
Accepted
time: 0ms
memory: 7968kb
input:
2 3 4
output:
490
result:
ok 1 number(s): "490"
Test #4:
score: 0
Accepted
time: 0ms
memory: 7860kb
input:
1 2 8
output:
45
result:
ok 1 number(s): "45"
Test #5:
score: 0
Accepted
time: 0ms
memory: 7900kb
input:
1 10 2
output:
66
result:
ok 1 number(s): "66"
Test #6:
score: 0
Accepted
time: 0ms
memory: 7972kb
input:
9 5 7
output:
371850968
result:
ok 1 number(s): "371850968"
Test #7:
score: 0
Accepted
time: 1ms
memory: 8052kb
input:
3 3 1
output:
20
result:
ok 1 number(s): "20"
Test #8:
score: 0
Accepted
time: 1ms
memory: 8052kb
input:
7 7 9
output:
166345303
result:
ok 1 number(s): "166345303"
Test #9:
score: 0
Accepted
time: 1ms
memory: 8056kb
input:
25 15 25
output:
850087558
result:
ok 1 number(s): "850087558"
Test #10:
score: 0
Accepted
time: 1ms
memory: 8004kb
input:
45 59 71
output:
659153227
result:
ok 1 number(s): "659153227"
Test #11:
score: 0
Accepted
time: 1ms
memory: 7980kb
input:
73 3 25
output:
683124269
result:
ok 1 number(s): "683124269"
Test #12:
score: 0
Accepted
time: 1ms
memory: 8008kb
input:
1 48 78
output:
446896916
result:
ok 1 number(s): "446896916"
Test #13:
score: 0
Accepted
time: 1ms
memory: 8056kb
input:
25 100 32
output:
966287506
result:
ok 1 number(s): "966287506"
Test #14:
score: 0
Accepted
time: 1ms
memory: 7872kb
input:
85 64 40
output:
125679545
result:
ok 1 number(s): "125679545"
Test #15:
score: 0
Accepted
time: 1ms
memory: 7928kb
input:
5 9 94
output:
620471576
result:
ok 1 number(s): "620471576"
Test #16:
score: 0
Accepted
time: 1ms
memory: 7996kb
input:
33 57 40
output:
637315057
result:
ok 1 number(s): "637315057"
Test #17:
score: 0
Accepted
time: 1ms
memory: 7952kb
input:
61 6 97
output:
362472796
result:
ok 1 number(s): "362472796"
Test #18:
score: 0
Accepted
time: 1ms
memory: 7912kb
input:
85 50 51
output:
192099209
result:
ok 1 number(s): "192099209"
Test #19:
score: 0
Accepted
time: 1ms
memory: 7924kb
input:
96 54 59
output:
714762612
result:
ok 1 number(s): "714762612"
Test #20:
score: 0
Accepted
time: 1ms
memory: 7992kb
input:
20 99 12
output:
772155662
result:
ok 1 number(s): "772155662"
Test #21:
score: 0
Accepted
time: 1ms
memory: 7880kb
input:
48 39 62
output:
670046604
result:
ok 1 number(s): "670046604"
Test #22:
score: 0
Accepted
time: 1ms
memory: 7892kb
input:
76 83 16
output:
976820079
result:
ok 1 number(s): "976820079"
Test #23:
score: 0
Accepted
time: 1ms
memory: 7924kb
input:
96 36 61
output:
20854557
result:
ok 1 number(s): "20854557"
Test #24:
score: 0
Accepted
time: 1ms
memory: 7888kb
input:
18 40 77
output:
261684871
result:
ok 1 number(s): "261684871"
Test #25:
score: 0
Accepted
time: 1ms
memory: 8056kb
input:
42 84 26
output:
458573307
result:
ok 1 number(s): "458573307"
Test #26:
score: 0
Accepted
time: 1ms
memory: 8004kb
input:
71 25 80
output:
875902815
result:
ok 1 number(s): "875902815"
Test #27:
score: 0
Accepted
time: 1ms
memory: 10036kb
input:
95 73 26
output:
922299967
result:
ok 1 number(s): "922299967"
Test #28:
score: 0
Accepted
time: 1ms
memory: 8004kb
input:
19 17 83
output:
494148696
result:
ok 1 number(s): "494148696"
Test #29:
score: 0
Accepted
time: 1ms
memory: 8028kb
input:
100 100 100
output:
192912055
result:
ok 1 number(s): "192912055"
Test #30:
score: 0
Accepted
time: 1ms
memory: 8004kb
input:
100 98 99
output:
412293529
result:
ok 1 number(s): "412293529"