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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#240808 | #6348. Egor Has a Problem | 45645A# | TL | 0ms | 0kb | C++17 | 1.1kb | 2023-11-05 19:29:43 | 2023-11-05 19:29:43 |
answer
#include <bits/stdc++.h>
using namespace std;
inline int read()
{
char ch;
while((ch=getchar())<'0'||ch>'9');
int res=ch-'0';
while((ch=getchar())>='0'&&ch<='9') res=res*10+ch-'0';
return res;
}
const int N=1000100;
const int mod=998244353;
int n,a[N],jc[N],ny[N];
int ksm(int x,int K)
{
int res=1;
while(K)
{
if(K&1) res=1ll*res*x%mod;
K>>=1;
x=1ll*x*x%mod;
}
return res;
}
int C(int n,int m)
{
return 1ll*jc[n]*ny[n-m]%mod*ny[m]%mod;
}
int mn[N],b[N];
int main()
{
n=read();int K=read();
jc[0]=1;
for(int i=1;i<=n;i++) a[i]=read(),jc[i]=1ll*jc[i-1]*i%mod;
ny[n]=ksm(jc[n],mod-2);
for(int i=n-1;i>=0;i--) ny[i]=1ll*ny[i+1]*(i+1)%mod;
mn[n+1]=n+1;
for(int i=n;i>=1;i--) mn[i]=min(mn[i+1],a[i]);
int tmp=0,ans=0;
for(int i=1;i<=n;i++)
{
int lst=0;
if(!tmp||a[i]>b[tmp]) b[lst=++tmp]=a[i];
else
{
int l=1,r=tmp;
while(l<=r)
{
int mid=l+r>>1;
if(b[mid]>a[i]) r=mid-1;
else l=mid+1;
}
b[lst=l]=a[i];
}
if(lst>=K&&a[i]<mn[i+1]) (ans+=C(lst-1,K-1))%=mod;
}
if(K&1) printf("%d",(mod-ans)%mod);
else printf("%d",ans);
return 0;
}
Details
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Test #1:
score: 0
Time Limit Exceeded
input:
6 2 6 11 21 47 120