Project Euler 8

8.cpp

#include <iostream>
#include <string.h>
#include <algorithm>

using namespace::std;

// Finds the maximum product of n sequential digits in an s-sized series.
long long findSeriesProduct(int a[], int s, int n, int i){
    // Base case
    if (n + i > s) return 0;
    // Keep track of the current max
    long long currentMax = 1;
    // Brute-force iterate over the current section of terms
    for (int j = 0; j < n; j++) currentMax *= a[i + j];
    // Look at the rest of the series until the base case is reached
    return max(currentMax, findSeriesProduct(a, s, n, i+1));
}

// Start of main
int main(void){

// Yeah . . . this should be from a file . . .
const char* theSeries = "73167176531330624919225119674426574742355349194934"
"96983520312774506326239578318016984801869478851843"
"85861560789112949495459501737958331952853208805511"
"12540698747158523863050715693290963295227443043557"
"66896648950445244523161731856403098711121722383113"
"62229893423380308135336276614282806444486645238749"
"30358907296290491560440772390713810515859307960866"
"70172427121883998797908792274921901699720888093776"
"65727333001053367881220235421809751254540594752243"
"52584907711670556013604839586446706324415722155397"
"53697817977846174064955149290862569321978468622482"
"83972241375657056057490261407972968652414535100474"
"82166370484403199890008895243450658541227588666881"
"16427171479924442928230863465674813919123162824586"
"17866458359124566529476545682848912883142607690042"
"24219022671055626321111109370544217506941658960408"
"07198403850962455444362981230987879927244284909188"
"84580156166097919133875499200524063689912560717606"
"05886116467109405077541002256983155200055935729725"
"71636269561882670428252483600823257530420752963450";

// Series as an array of ints
int* numSeries = new int[strlen(theSeries)];
// String converstion to int array
for (int i = 0; i < strlen(theSeries); i++) numSeries[i] = theSeries[i] - '0';
// Answer plz
long long answer = findSeriesProduct(numSeries, 1000, 13, 0);
cout << answer;
}
//  End of main