problem8.cpp

#include <iostream>
#include <string>

using namespace std;

int main() {
    string input = "73167176531330624919225119674426574742355349194934"
            "96983520312774506326239578318016984801869478851843"
            "85861560789112949495459501737958331952853208805511"
            "12540698747158523863050715693290963295227443043557"
            "66896648950445244523161731856403098711121722383113"
            "62229893423380308135336276614282806444486645238749"
            "30358907296290491560440772390713810515859307960866"
            "70172427121883998797908792274921901699720888093776"
            "65727333001053367881220235421809751254540594752243"
            "52584907711670556013604839586446706324415722155397"
            "53697817977846174064955149290862569321978468622482"
            "83972241375657056057490261407972968652414535100474"
            "82166370484403199890008895243450658541227588666881"
            "16427171479924442928230863465674813919123162824586"
            "17866458359124566529476545682848912883142607690042"
            "24219022671055626321111109370544217506941658960408"
            "07198403850962455444362981230987879927244284909188"
            "84580156166097919133875499200524063689912560717606"
            "05886116467109405077541002256983155200055935729725"
            "71636269561882670428252483600823257530420752963450";

    unsigned long long greatest = 0;

    unsigned int length = 13;

    for(int i = 0; i < input.size() - length; i++) {
        unsigned long long current = 1;
        for (int j = 0; j < length; j++) {
            current *= input.at(i + j) - '0';
        }
        if(current > greatest)
            greatest = current;
    }

    cout << "Problem 8 solution is " << greatest;

    return 0;
}