# My Weblog

## Project Euler Problem 303

For Project Euler problem 303 ,a simple brute force is enough to kill but DP can be used improve the run time which many solvers did. This problem has nice pattern about 9,99,999 , 9999 which makes brute force to killed by memory [Mine memory was 768MB ] limit exceed. For 9 the number is 12222 ,99——1122222222 , 999 ———111222222222222 and 9999 ———–11112222222222222222. Approximately 5 minutes on my laptop.

```#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include<gmpxx.h>
typedef long long _int;
using namespace std;
struct state
{
_int n;
/*bool operator<(state s) const
{
return this->n > s.n;
}*/
};
int main()
{

_int sum=0;
for(int i=1;i<=10000;i++)
{

if(i==9) { sum+=_int(1358LL);continue;}
if(i==99){sum+=_int(11335578LL);continue;}
if(i==999){ sum+=_int(111333555778LL);continue;}
if(i==9999){sum+=_int(1111333355557778LL);continue;}
queue<state> Q;
Q.push((state){1});
Q.push((state){2});
bool t=true;
while(t)
{
state tmp=Q.front();Q.pop();
if(tmp.n%i==0) {/*cout<<i<<" "<<tmp.n<<" "<<tmp.n/i<<endl;*/t=false;sum+=(tmp.n/i);}
for(int i=0;i<=2;i++) Q.push((state){10*tmp.n+i });

}
}
cout<<endl<<sum<<endl;
}
```