Submission #3459446
Source Code Expand
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cassert> #define ll long long #define MOD 1000000007 using namespace std; inline int read(){ int re=0,flag=1;char ch=getchar(); while(!isdigit(ch)){ if(ch=='-') flag=-1; ch=getchar(); } while(isdigit(ch)) re=(re<<1)+(re<<3)+ch-'0',ch=getchar(); return re*flag; } int n; ll dp[2000010],sum[2000010]; void add(ll &a,ll b){ a+=b; if(a>=MOD) a-=MOD; } int main(){ n=read(); int i; dp[1]=1; for(i=1;i<=n;i++){ if(i>=3) add(dp[i],sum[i-3]); add(dp[i],dp[i-1]); (sum[i]=sum[i-1]+dp[i])%=MOD; } ll ans=0; for(i=1;i<n;i++) add(ans,dp[i]*(n-1)%MOD*(n-1)%MOD); for(i=1;i<n-1;i++) add(ans,dp[i]*(i+1)%MOD); add(ans,(dp[n]*n+dp[n-1]*(n-1))%MOD); cout<<ans<<'\n'; }
Submission Info
Submission Time | |
---|---|
Task | F - Infinite Sequence |
User | dedicatus545 |
Language | C++14 (GCC 5.4.1) |
Score | 1000 |
Code Size | 798 Byte |
Status | AC |
Exec Time | 18 ms |
Memory | 18688 KB |
Judge Result
Set Name | Sample | All | ||||
---|---|---|---|---|---|---|
Score / Max Score | 0 / 0 | 1000 / 1000 | ||||
Status |
|
|
Set Name | Test Cases |
---|---|
Sample | 0_000.txt, 0_001.txt |
All | 0_000.txt, 0_001.txt, max_1000000.txt, max_999745.txt, max_999880.txt, max_999999.txt, min_1.txt, rnd_14.txt, rnd_22.txt, rnd_25002.txt, rnd_2956.txt, rnd_3.txt, rnd_380467.txt, rnd_407774.txt, rnd_52228.txt, rnd_68.txt, rnd_804783.txt, rnd_85984.txt, rnd_894324.txt, rnd_93.txt, rnd_963981.txt, rnd_968416.txt |
Case Name | Status | Exec Time | Memory |
---|---|---|---|
0_000.txt | AC | 2 ms | 2304 KB |
0_001.txt | AC | 13 ms | 14592 KB |
max_1000000.txt | AC | 18 ms | 18688 KB |
max_999745.txt | AC | 18 ms | 18688 KB |
max_999880.txt | AC | 18 ms | 18688 KB |
max_999999.txt | AC | 18 ms | 18688 KB |
min_1.txt | AC | 2 ms | 2304 KB |
rnd_14.txt | AC | 2 ms | 2304 KB |
rnd_22.txt | AC | 2 ms | 2304 KB |
rnd_25002.txt | AC | 2 ms | 2432 KB |
rnd_2956.txt | AC | 2 ms | 2304 KB |
rnd_3.txt | AC | 2 ms | 2304 KB |
rnd_380467.txt | AC | 8 ms | 10496 KB |
rnd_407774.txt | AC | 9 ms | 10496 KB |
rnd_52228.txt | AC | 2 ms | 2688 KB |
rnd_68.txt | AC | 2 ms | 2304 KB |
rnd_804783.txt | AC | 15 ms | 16640 KB |
rnd_85984.txt | AC | 3 ms | 2944 KB |
rnd_894324.txt | AC | 17 ms | 18688 KB |
rnd_93.txt | AC | 2 ms | 2304 KB |
rnd_963981.txt | AC | 18 ms | 18688 KB |
rnd_968416.txt | AC | 18 ms | 18688 KB |