ENG  RUSTimus Online Judge
Online Judge
Problems
Authors
Online contests
About Online Judge
Frequently asked questions
Site news
Webboard
Links
Problem set
Submit solution
Judge status
Guide
Register
Update your info
Authors ranklist
Current contest
Scheduled contests
Past contests
Rules
back to board

Discussion of Problem 1044. Lucky Tickets. Easy!

#include <iostream>
using namespace std;

int main() {

    int arr[4] = {10, 670, 55252, 4816030};
    short m;

    cin >> m;
    cout << arr[m / 2 - 1];
    return 0;
}

//hey; can you guess how i got these values?(think of the simplest solution)

Edited by author 15.02.2013 04:31
Nothing funny.
if we are not too creative to calculate this on paper and there is no forum to take solution just do backtracking it works fine 1 second and something
#include <iostream>
using namespace std;
int x[10], n, cont = 0;
void back(int k)
{
    if(k == n)
    {
        int s1 = 0, s2 = 0;
        for(int i = 0; i < n / 2; i++)
        {
            s1 += x[i];
        }
        for(int i = n / 2; i <= n; i++)
        {
            s2 += x[i];
        }
        if(s2 == s1)
            cont++;
    }
    else
        for(int i = 0; i <= 9; i++)
        {
            x[k] = i;
            back(k + 1);
        }
}
int main () {
    cin >> n;
    back(0);
    cout << cont;
    return 0;
}