The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832.
73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450
Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
Uncomfortably large 1000 digit number is getting stored as a string to begin with.. it's just too big to fit into the regular number types. Thought was I could either iterate through all possible sets of 13 then see if 0 is part of the set. If 0 is part of the set, obviously the product will be 0 which is less than a set without 0.. so just get rid of those possibilities. If we can get a product out of it that isn't 0, we are going to parse each string into its digit using LINQ then aggregate it into a product. Then compare the product to the last highest product. If it is higher, set the current highest product to the new product.
23514624000 is the solution.
73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450
Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?
Uncomfortably large 1000 digit number is getting stored as a string to begin with.. it's just too big to fit into the regular number types. Thought was I could either iterate through all possible sets of 13 then see if 0 is part of the set. If 0 is part of the set, obviously the product will be 0 which is less than a set without 0.. so just get rid of those possibilities. If we can get a product out of it that isn't 0, we are going to parse each string into its digit using LINQ then aggregate it into a product. Then compare the product to the last highest product. If it is higher, set the current highest product to the new product.
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
string thousandDigitNum =
"/*insert giant number here from their website*/";
string thirteenDigitString = null;
long newProduct = 0;
long currHighestProduct = 0;
for (int i = 0; i < (thousandDigitNum.Length -13); i++)
{
thirteenDigitString = thousandDigitNum.Substring(i, 13);
if (thirteenDigitString.Contains("0")) continue;
newProduct = thirteenDigitString.Select(digit => long
.Parse(digit.ToString()))
.Aggregate((a, b) => a*b);
if (newProduct > currHighestProduct) currHighestProduct = newProduct;
}
stopwatch.Stop();
Console.WriteLine("The highest value is: " + currHighestProduct + ". And the time elapsed is:" + stopwatch.Elapsed);
Console.ReadLine();
23514624000 is the solution.













