#include<iostream>
using namespace std;
int GCD( int a, int b )
{
    a = abs( a );
    b = abs( b );

    while ( b )
    {
        int tmp = a % b;
        a = b;
        b = tmp;
    }
    return ( a );
}
int main()
{ int s=0,n,i;
   cin>>n;
   for(i=1;i<=n/2;i++)
         if(GCD(n,i)%n==1)
         s++;
         cout<<s;
    system("pause");
    return 0;
}

If you have WA#7 check that your program works correct with strings with symbols "{" and "//"

#include <iostream>

using namespace std;


int main()
{
    int k,a[1001],i(0),s(0),maxs(0),j(0);

    cin >> k;
    while(i<k)
    {
        cin >> a[i];
        i++;
    }

    for (i=0; i<k; i++){
        if (a[i]==a[i+1] && a[i]==a[i+2])
        {
            s = a[i]*3;
            j = i+2;
        }
        if (s > maxs)
        {
            maxs = s;
            s = 0;
        }
    }
    cout<<maxs<<"\n"<<j<<endl;
}

Edited by author 10.02.2014 22:44

why???
#include <iostream>
//#include <stdlib.h>
//#include <stdio.h>
#include <string.h>
using namespace std;
int i,o,tp,nm;
struct Tpart
{
    int val [24];
    int k;
    Tpart *lst;

};
char com[100];
Tpart stk[1024];
int Pop(Tpart *p)
{
    if(p->k>0) return p->val[--(p->k)];
    else
    {
        Tpart *e=p;
    p=p->lst;
    delete e;
    return p->val[--(p->k)];
    }};
void Push(Tpart *p, int val)
{
    if((p->k)<24) (p->val)[(p->k)++]=val;
        else
    {
        Tpart *uk= new Tpart;
        uk->lst=p;
        p=uk;
        p->k=0;
        (p->val)[(p->k)++]=val;
        }
    return;
}
int main() {

    int n; cin>>n;
    for(int j=0;j<n;j++)
    {
        cin>>com;
        if (strcmp(com,"PUSH")==0)
        {
            cin>>nm>>tp;
            Push(&stk[nm-1],tp);
            }
        if (strcmp(com,"POP")==0)
                {
                    cin>>nm;
                    cout<<Pop(&stk[nm-1])<<endl;}
        }
    return 0;
}

Just give me some hint pls: intueor19@gmail.com
I really don't understand what is wrong... It passes all tests on that forum but still has WA15

#include <iostream>
#include <vector>

using namespace std;

vector < int > pm (30, 0);
vector < vector < char > > d (31, vector < char > (1000000, 0));
int n;

void printAnswer (int, int);

int main () {
    cin >> n;

    pm[0] = 1 % n;
    for (int i = 1; i < 30; ++i)
        pm[i] = (pm[i - 1] * (10 % n)) % n;

    d[0][0] = 1;
    char found = 0;

    for (int i = 1; i <= 30; ++i) {
        int m1 = pm[i - 1];
        int m2 = ((2 % n) * pm[i - 1]) % n;

        if (d[i - 1][(n - m1) % n] != 0) {
            printAnswer (1, i);
            found = 1;
            break;
        }

        if (d[i - 1][(n - m2) % n] != 0) {
            printAnswer (2, i);
            found = 1;
            break;
        }

        for (int j = 0; j < n; ++j) {
            if (d[i - 1][j] == 0)
                continue;

            d[i][(j + m2) % n] = 2;
            d[i][(j + m1) % n] = 1;
        }
    }

    if (!found)
        cout << "Impossible";

    return 0;
}


void printAnswer (int digit, int lvl) {
    int k = 0;
    int x, j;

    while (lvl != 0) {
        cout << (int)digit;
        j = ((digit % n) * pm[lvl - 1]) % n;
        x = (k >= j) ? (k - j) : (n - j + k);
        digit = d[lvl - 1][x];
        k = x;
        --lvl;
    }

    return;
}

I got AC with other code but I still don't understand what's wrong with this one. Help me PLS!!!

Edited by author 09.02.2014 19:37

Could you tell me some useful test, if you had the same problem?! Thanks ^_^

can you tell me test 35? i have WA

The answer for "30 1 2012":

mon........2....9...16...23..[30]
tue........3...10...17...24...31
wed........4...11...18...25.....
thu........5...12...19...26.....
fri........6...13...20...27.....
sat........7...14...21...28.....
sun...1....8...15...22...29.....

between first and second column there are exactly 4(!) '.';

Considering my submissions, I concluded that in the 15-th test there is a radiobeacon for which its coordinates can't be integers between 1 and 200. If for such radiobeacons output "UNKNOWN", the solution gets AC. This does not fit with the statement.

I didn't use any long arithmethic but i think it should passes the first test. But judge says WA !!! Help please if you can


#include <iostream>

using namespace std;

long long d[10001][2];

int main () {
    int n, k;

    cin >> n >> k;

    d[0][0] = 1;
    d[0][1] = 0;

    int i, j;

    for (i = 1; i <= n; ++i) {

        d[i][1] = 0;
        for (j = 1; j <= k; ++j) {
            if (n - j < 0)
                continue;

            d[i][1] += d[i - j][0];
        }

        d[i][0] = d[i - 1][0] + d[i - 1][1];
    }

    cout << d[n][0] + d[n][1];

    return 0;
}

I've solved it using bruteforce for small K and then guessing the formula. But I still don't know the proof. Can anybody write it?

1) "after every fall, the kinetic energy of the ball decreases by a factor of K". So if K > 1, that means the energy becomes negative? E_2 = E_1 - E_1*K might be interpreted to be what you mean when you say something decreases by some factor.
2) "Your task is to determine the maximal distance from the point of throwing that the ball can fly." If the ball is pitched straight up, it will fly some maximal distance from the point of throwing before it reaches the ground again. You should probably exactly what you mean.

I'm newby here and I didn't solve this kind of tasks before.
I know, that must be very easy, give me please some pieces of advice to solve it.

Hey, guys, it is not serious, really ...... I had wa4 with EPS = 1e-8 .... when I've changed EPS = 1e-6 I got AC...

Edited by author 06.02.2014 18:13

Does anyone know what's this test like?

using System;
namespace ConsoleApplication4
{
    class Program
    {
        static void SQRT(UInt64 sum)
        {
            double ima_ans = Convert.ToDouble(Math.Sqrt(Convert.ToDouble(sum)));
            Console.WriteLine(Convert.ToDouble((Math.Round(ima_ans = ima_ans * 10000)) / 10000));
        }
        static void Main(string[] args)
        {
            string save_str=null;
            string str = Console.ReadLine();
            int i = str.Length;
            int  k;
            UInt64 sum;
            i = i - 1;
            while (i >= 0)
            {
                k = 0;
                while (i >= 0 && str[i] != ' ')
                {
                    k = 1;
                    save_str += str[i];
                    i = i - 1;
                }
                sum = Convert.ToUInt64(save_str);
                if (sum > 0 && sum <= Math.Pow(10, 18) || k == 1)
                    SQRT(sum);
                save_str = null;
                i = i - 1;
            }
            Console.ReadLine();
        }
    }
}

Don't have any idea, give me that or similar test please.

#include <iostream>

using namespace std;
int main()
{
    int a,b;
    cin>>a;
    if(a==0 && a<=10000)
    cout<<"1";
    else
    {
    if(a>0 && a<=10000)
    cout<<((a*(a+1))/2);
    else
    { if(a<=10000){
        b=-((((-a)*((-a)+1))/2)-1);

        cout<<(b);}
        else
        cout<<"error";}

    }
return 0;
}

Edited by author 05.02.2014 01:45

Ok, just search biggest prime number :)

Edited by author 04.02.2014 22:13

more than one registrations ;)