Topic link ：hdu 4828 Grids

The main idea of the topic ： A little .

Their thinking ： Think of the previous line as a stack , The next line is seen as out of the stack , So the persistent solution is the Cartland number , It is solved by recursion .

``````#include <cstdio>
#include <cstring>
typedef long long ll;
const int N = 1000005;
const ll MOD = 1e9+7;
ll dp[N];
ll extendGcd(ll a, ll b, ll& x, ll& y) {
if (b == 0) {
x = 1;
y = 0;
return a;
}
ll d = extendGcd(b, a%b, y, x);
y -= a / b * x;
return d;
}
ll solve (ll n) {
ll x, y;
ll tmp = extendGcd(n + 1, MOD, x, y);
x = (x % MOD + MOD) % MOD;
return x;
}
void init () {
dp[1] = 1;
dp[2] = 2;
for (ll i = 3; i < N; i++)
dp[i] = (dp[i-1] * (4 * i - 2) % MOD * solve(i)) % MOD;
}
int main () {
int cas, n;
scanf("%d", &cas);
init();
for (int i = 1; i <= cas; i++) {
scanf("%d", &n);
printf("Case #%d:\n%lld\n", i, dp[n]);
}
return 0;
}``````

## hdu 4828 Grids( Expand Euclid + Carter LAN number ) More articles about

1. NOIP2012 Expand Euclid

Pull the board ,,, Shut up Did I say that data structure is boring ,,, I want to take back ,,, The number theory started today is still disgusting , I feel dizzy all morning Let's start with Euclid #include <cstdio> void gcd ...

2. poj 1061 Frog dating Expand Euclidean template

// poj 1061 Frog dating Expand Euclidean template // Pay attention to exgcd when , Guarantee a,b Positive number , If the final answer is negative , It's going to add a membrane #include <cstdio> #include ...

3. bzoj4517: [Sdoi2016] Permutation count -- mathematics + Expand Euclid

This is a math problem , From the title we can see ,m The way to get a stable number is Cnm Then left n-m This book , Because the number is i You can't put your books in i Location , Therefore, the number of methods should be determined by the staggered formula , namely D(n-m) The staggered formula :D[i]=(i-1)*(D[i-1]+ ...

4. POJ 2891 Strange Way to Express Integers（ Expand Euclid ）

Description Elina is reading a book written by Rujia Liu, which introduces a strange way to express ...

5. POJ1061 Frog dating - Expand Euclid

Description Two frogs met on the Internet , They had a good chat , So it's necessary to meet . They are happy to find that they live on the same latitude line , So they agreed to go west , Until we meet . But before they set out, they forgot a very important thing ...

6. BZOJ-2242 Calculator Fast power + Expand Euclid +BSGS（ Number theory is three in one ）

Dirty... Dirty 2242: [SDOI2011] Calculator Time Limit: 10 Sec Memory Limit: 512 MB Submit: 2312 Solved: 917 [Submit][S ...

7. BZOJ-1407 Savage enumeration + Expand Euclid （+ Chinese remainder theorem ？？）

zky The strength of senior students ACM Competition system test , and Big news (YveH) and Wallace (hjxcpg) organize a team ...2h 10T, Start I do A, Big news B, Wallace C, So I started : But the first question is the giant ghost animal , Think about 40min Discovery seems impossible ...

8. poj2891 Expand Euclid

//Accepted 164 KB 16 ms // Expand Euclid //m=a1*x+b1 --(1) //m=a2*(-y)+b2 --(2) //->a1*x+a2*y=b2-b1 // From Europe to Japan ...

9. [zoj 3774]Power of Fibonacci number theory ( Second surplus Expand Euclid Sum of equal ratio sequence )

Power of Fibonacci Time Limit: 5 Seconds      Memory Limit: 65536 KB In mathematics, Fibonacci numbe ...

## Random recommendation

1. Aspose.Cells export Excel（1）

utilize Aspose.Cells export excel Attention problem 1.DataTable To deal with 2. Encoding , Easy to download Chinese name file 3. Don't forget Aspose.Cells.dll( You can search online by yourself ) public ...

2. gifted with an extraordinary retentive memory JS Regular expressions

Regular expressions , There are people like me , I've learned it several times, but I'm still confused , I always understand when I study , I forgot all about it . ok , In fact, I didn't practice enough , The so-called learning from the past , I can be a teacher , Today, let me review the proud regular expression . Why regular expressions ...

3. robots

User-agent: Baiduspider Disallow: /w? Allow: / User-agent: Googlebot Allow: / User-agent: Googlebot- ...

4. visit IIS Metabase failure resolution

problem : Failed to access metadata Details visit IIS Metabase failed . explain : Execute the current Web During the period of the request , An unhandled exception occurred . Please check the stack trace information , To learn more about the error and the source of the error in the code . Unusual details ...

5. Windows Network sharing permission settings

There are two permission settings for file sharing , As long as you understand these two permission settings, you can use them flexibly in domain control . The first is network sharing rights Sharing permission is a means to control users' access to shared folders through the network , Sharing rights are only valid if the user accesses through the network , Local users are not subject to this permission ...

6. Use Css Intercepting string

white-space:nowrap; /* No word wrap */ overflow:hidden; /* Hide overflow */ text-overflow:ellipsis; /* Overflow text using ... ...

7. Common objects API、 additional ： Gather to supplement

Basic data type object wrapper class : To facilitate the operation of basic data type values , Encapsulate it as an object , The attributes and behaviors defined in the object enrich the operation of the data . The class used to describe the object is called the basic data type object wrapper class . byte——Byte short ...

8. C# CheckedListBox How to use control

1. Add checkedListBox1.Items.Add(" Blue "); checkedListBox1.Items.Add(" Red "); checked ...

9. Windows Built in security principals

from :https://blog.csdn.net/xcntime/article/details/51746148 Reading guide : about Windows In particular, the built-in security agent needs to pay attention to : You can't create it . Rename and delete them , ...

10. Use rpm-build Make nginx Of rpm package

2014-11-27 11:05:49   One .RPM Classification of packages RPM There are five basic operating functions : install . uninstall . upgrade . Query and verify . linux Software packages fall into two categories : (1) Binary class package , Include rpm Installation package ( Generally divided into i ...