package pro.szewczyk.euler.problems;

import pro.szewczyk.euler.AbstractProblem;

/**
 * Find the greatest product of five consecutive digits in the 1000-digit number.
 * 
 * @author Mateusz Szewczyk
 */
public class Problem8 extends AbstractProblem<Integer> {

    private static final char[] array = "7316787653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450"
            .toCharArray();

    private static final int CHAR_ZERO_BASE = '0';

    /**
     * Find the greatest product of five consecutive digits in the 1000-digit number.
     */
    @Override
    public Integer solveProblem() {
        int tmp = 1;
        int ret = 0;
        int lastChar = 1;

        int skipDivide = 5;

        for (int i = 0; i < array.length; i++) {
            int newNumber = array[i] - CHAR_ZERO_BASE;

            if (newNumber == 0) {
                tmp = 1;
                skipDivide = 5;
                lastChar = 1;
                i += 3;
                continue;
            }

            tmp = tmp * newNumber;

            if (skipDivide-- <= 0) {
                tmp /= lastChar;
            }

            lastChar = newNumber;

            if (tmp > ret) {
                ret = tmp;
            }
        }

        return ret;
    }

    public static void main(final String[] args) {
        new Problem8().printSolution();
    }
}

solve problem 8