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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 |
---|---|---|---|---|---|---|---|---|---|
#693434 | #6410. Classical DP Problem | LYY_yyyy | WA | 3ms | 101696kb | C++14 | 1.1kb | 2024-10-31 16:09:12 | 2024-10-31 16:09:23 |
Judging History
answer
#include<bits/stdc++.h>
#define pb emplace_back
#define ll long long
#define all(b) b.begin(),b.end()
using namespace std;
int n,a[5010],dp[5010][5010],b[5010];
const int mod=998244353;
inline void add(int &x,int y)
{
x+=y;
if(x>=mod) x-=mod;
}
int main()
{
ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>n;
int k=0;
for(int i=1;i<=n;i++) cin>>a[i],k=max(k,min(n-i+1,a[i]));
cout<<k<<' ';
int t=a[n-k],ans=0;
dp[n-k][0]=1;
for(int i=n-k+1;i<=n;i++)
{
for(int j=0;j<=t;j++)
{
add(dp[i][j],1ll*(a[i]-t+j)*dp[i-1][j]%mod);
if(j) add(dp[i][j],1ll*dp[i-1][j-1]*(t-j+1)%mod);
}
}
add(ans,dp[n][t]);
memset(dp,0,sizeof(dp));
dp[n-k][0]=1;
for(int i=1;i<=n;i++) b[n]++,b[n-a[i]]--;
for(int i=n;i>=1;i--) b[i]+=b[i+1],a[i]=b[i];
for(int i=n-k+1;i<=n;i++)
{
for(int j=0;j<=t;j++)
{
add(dp[i][j],1ll*(a[i]-t+j)*dp[i-1][j]%mod);
if(j) add(dp[i][j],1ll*dp[i-1][j-1]*(t-j+1)%mod);
}
}
add(ans,dp[n][t]);
int fac=1;
for(int i=1;i<=k;i++) fac=1ll*fac*i%mod;
add(ans,mod-fac);
cout<<ans;
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 101696kb
input:
3 1 2 3
output:
2 6
result:
ok 2 number(s): "2 6"
Test #2:
score: 0
Accepted
time: 0ms
memory: 101624kb
input:
1 1
output:
1 1
result:
ok 2 number(s): "1 1"
Test #3:
score: -100
Wrong Answer
time: 3ms
memory: 101636kb
input:
2 1 1
output:
1 1
result:
wrong answer 2nd numbers differ - expected: '2', found: '1'