long window_prod = 1;

int num_zero = 0;

for (int i = 0; i < window_size; i++) {

int pointer = (int) n[i] - '0';

if (pointer == 0)

num_zero += 1;

else

window_prod *= pointer;

}

long max_prod = num_zero == 0 ? window_prod : 0;

for (int i = window_size; i < n.length(); i++) {

int forward = (int) n[i] - '0';

int backward = (int) n[i-window_size] - '0';

if (backward == 0)

num_zero --;

else

window_prod /= backward;

if (forward == 0)

num_zero ++;

else

window_prod *= forward;

if (num_zero == 0) {

max_prod = max(window_prod, max_prod);

}

}

return max_prod;

string n = ""

"73167176531330624919225119674426574742355349194934"

"96983520312774506326239578318016984801869478851843"

"85861560789112949495459501737958331952853208805511"

"12540698747158523863050715693290963295227443043557"

"66896648950445244523161731856403098711121722383113"

"62229893423380308135336276614282806444486645238749"

"30358907296290491560440772390713810515859307960866"

"70172427121883998797908792274921901699720888093776"

"65727333001053367881220235421809751254540594752243"

"52584907711670556013604839586446706324415722155397"

"53697817977846174064955149290862569321978468622482"

"83972241375657056057490261407972968652414535100474"

"82166370484403199890008895243450658541227588666881"

"16427171479924442928230863465674813919123162824586"

"17866458359124566529476545682848912883142607690042"

"24219022671055626321111109370544217506941658960408"

"07198403850962455444362981230987879927244284909188"

"84580156166097919133875499200524063689912560717606"

"05886116467109405077541002256983155200055935729725"

"71636269561882670428252483600823257530420752963450";

int window_size = 13;

long max_prod = find_max_product(n, window_size);

if (log) cout << max_prod << endl;