Project Euler 35

#include <iostream>
#include <bitset>
using namespace std;
const int n = 1000000;
bitset<n+1> criba;
void generarCriba()
{
    criba[0] = criba[1] = true;
    for(int i = 2 ; i*i<=n; i++)
        if(!criba[i])
            for(int j = i+i; j<=n; j +=i )
                criba[j]= true;

}
int main()
{
    generarCriba();
    int cont = 4;//2,3,5,7 ya cuentan como primos circulares
    int cc = 1;
    int sncc= 100;
    int nc = 10;
    for(int i = 10 ; i<n; i++)
    {
        if(i==sncc)
        {
            cc++;
            sncc *=10;
            nc *= 10;
        }
        if(!criba[i])
        {
            int num = i;
            int c = 0;

            for(int u = 1 ; u<=cc; u++)
            {
                int d = num%10;
                num /= 10;
                num = (d*nc+num);
                if(!criba[num])
                    c++;
                else
                    break;
            }

            if(c == cc)
                cont++;
        }
    }
    cout <<"Resultado final = "<< cont<< endl;
    return 0;
}

Project Euler 34

#include <iostream>

using namespace std;

int main()
{
    int sum = 0 ;
    int fac[10] = {1,1,2};
    for(int i = 3; i<=9; i++)
        fac[i] = i*fac[i-1];
    int num = 0;
    int n[5]= {0};
    for(n[0] = 0 ; n[0]<10 ; n[0]++)
        for(n[1] = 0 ; n[1]<10 ; n[1]++)
            for(n[2] = 0 ; n[2]<10 ; n[2]++)
                for(n[3] = 0 ; n[3]<10 ; n[3]++)
                    for(n[4]= 0 ; n[4]<10 ; n[4]++)
                    {
                        int pos = 0 ;
                        while(pos <=4 && n[pos]==0)
                            pos++;
                        if(fac[n[0]]+fac[n[1]]+fac[n[2]]+fac[n[3]]+fac[n[4]]-pos==num)
                        {
                            cout << n[0] << "! + ";
                            cout << n[1] << "! + ";
                            cout << n[2] << "! + ";
                            cout << n[3] << "! + ";
                            cout << n[4] << "! = " << num<< endl;

                            sum += num;
                        }
                        num++;
                    }
    cout << sum-3<< endl;
    /*Le restamos 3 por que en el enunciado
      indica que no hay que sumar 1! = 1 y 2! = 2
        */
    return 0;
}

Project Euler 33

#include <iostream>

using namespace std;

int mcd(int a,int b)
{
    int c;
    if(b>a)
    {
        c = a;
        a = b;
        b = c;
    }
    c = a%b;
    while(c > 0)
    {
        a = b;
        b = c;
        c = a%b;
    }
    return b;
}

int main()
{
    int mcdiv;
    int de,nu;
    int resultadoden  = 1;
    int resultadonum = 1;
    for(int num = 10; num<=50; num++)
        for(int den = 10; den <= 99 ; den++)
        {
            mcdiv = mcd(num,den);
            if(num != den && mcdiv!=1 && mcdiv%10!=0)
            {
                de = den/mcdiv;
                nu = num/mcdiv;
                int dat1[2]= {num/10,num%10};
                int dat2[2]= {den/10,den%10};
                for(int i=0; i<=1; i++)
                    for(int j = 0; j<=1; j++)
                        if(dat1[i]!=0 && dat2[j]!=0 &&
                                dat1[i]%nu==0 &&
                                dat2[j]%de==0 &&
                                (dat1[i]/nu)==(dat2[j]/de) &&
                                (dat1[(i+1)%2]==dat2[(j+1)%2]))
                        {
                            cout << num<<"/"<<den<<" = "<<dat1[i]<<"/"<<dat2[j]<<endl;
                            resultadoden *= den;
                            resultadonum *= num;
                        }
            }
        }
    cout << "Resultado final = "<< resultadoden/mcd(resultadonum,resultadoden) <<endl;

    return 0;
}

Project Euler 32

#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <set>
#include <numeric>
using namespace std;
int factorial(int n)
{
    int f  = 1;
    while(n>0)
        f *= n--;
    return f;
}
int main()
{
    set<int> guardar ;
    string cad =  "123456789";
    int tam =  cad.length();
    int n1,n2,n3,i,j;
    int fac = factorial(tam);

    for(int n = 0 ; n < fac; n++)
    {
        for(i = 1 ; i <=(tam-2) ; i++ )
        {
            n1 = atoi(cad.substr(0,i).data());
            for(j = 1 ; j <= (tam-i-1); j++)
            {
                n2 = atoi(cad.substr(i,j).data());
                n3 = atoi(cad.substr(i+j,tam-i+j).data());
                if((n1*n2) == n3)
                {
                    cout << n1 << " x "<<n2 <<" = "<<n3<<endl;
                    guardar.insert(n3);
                }
            }
        }
        next_permutation(cad.begin(),cad.end());
    }
    cout << "Resultado Final = "<<accumulate(guardar.begin(),guardar.end(),0)<<endl;
    return 0;
}

Project Euler 40

#include <iostream>
#include <math.h>
using namespace std;
//metodo para obtener el i-esimo caracter de la concatenacion de 1,2,3,4,5...
int d(int i)
{
    int cd = 0; //cantidad de digitos
    int cda = 0; //cantidad de digitos acumulados
    int scd = 0; //siguiente cantidad de dtitos
    while( cda + scd < i)
    {
        cda += scd;
        cd++;
        scd =  (pow(10,cd)-pow(10,cd-1))*cd;
    }
    int numactual = pow(10,cd-1)-1;//numero actual hasta el cual se sumo
    while(cda < i)
    {
        cda += cd;
        numactual++;
    }
    int csp = (cda-i);
    while(csp--) numactual /= 10;
    return numactual%10;
}
int main()
{
    cout << d(1)*d(10)*d(100)*d(1000)*d(10000)*d(100000)*d(1000000)<<endl;
    return 0;
}

Project Euler 39

#include <iostream>
using namespace std;
int main()
{
    int v[1001], a, b, c;
    for( a = 1000 ; a >= 0 ; a--) v[a] = 0 ;
    for ( c = 1; c <= 1000; c++)
        for ( b = 1; b < c; b++)
            for ( a = 0; a <= b; a++)
                if(a+b>c && b-a<c && a+b+c <= 1000 && c*c == a*a+b*b)
                    v[a+b+c]++;
    b = 0 ;
    for ( a = 0; a <= 1000; a++)
        if(v[a]>v[b])
            b = a;
    cout << b << endl;
    return 0;
}

Project Euler 38

public class Problema38 {
 static boolean isPandigital(String num){
  if(num.length()!=9)
   return false;
  for (int i = 1; i < 10; i++) 
   if(!num.contains(""+i))
    return false;
  return true;
 }
 public static void main(String[] args) {
  String max = "123456789";
  for (int i = 9; i < 10000; i++) {
   int m = 1;
   String sol = "";
   while(sol.length()<9){
    sol += (i*m);
    m++;
   }
   if(sol.length()==9)
    if(isPandigital(sol))
     if(sol.compareTo(max)>0)
      max = sol;
  }
  System.out.println(max);
 }
}