Problem #31

Heres my code at solving this problem...I also added a timer into the code to calculate how quickly it solves the problems, it solved this one in 0.078 seconds.

#include <iostream>
#include <ctime>

using namespace std;

int main()
{
    clock_t start = clock();
    int total = 0;

    for (unsigned int i = 0; i <= 200; i++)
        for (unsigned int j = 0; i + j * 2 <= 200; j++)
            for (unsigned int k = 0; i + j * 2 + k * 5 <= 200; k++)
                for (unsigned int l = 0; i + j * 2 + k * 5 + l * 10 <= 200; l++)
                    for (unsigned int m = 0; i + j * 2 + k * 5 + l * 10 + m * 20 <= 200; m++)
                        for (unsigned int n = 0; i + j * 2 + k * 5 + l * 10 + m * 20 + n * 50 <= 200; n++)
                            for (unsigned int o = 0; i + j * 2 + k * 5 + l * 10 + m * 20 + n * 50 + o * 100 <= 200; o++)
                                for (unsigned int p = 0; i + j * 2 + k * 5 + l * 10 + m * 20 + n * 50 + o * 100 + p * 200 <= 200; p++)
                                    if (i * 1 + j * 2 + k * 5 + l * 10 + m * 20 + n * 50 + o * 100 + p * 200 == 200)
                                        total++;

    cout << total << endl 
         << "Process took " << (static_cast<double> (clock()) - start) / CLOCKS_PER_SEC << " seconds." << endl;

    system ("pause");
    return 0;
}