Product of K digits in an N digit Number Revision as of 14:25, 23 July 2014 by Arjun Suresh (talk | contribs) (diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Find the greatest product of $K$ consecutive digits in the $N$ digit number.

Input Format

First line contains $T$ that denotes the number of test cases. First line of each test case will contain two integers $N$ & $K$. Second line of each test case will contain a $N$ digit integer.

Output Format

Print the required answer for each test case.

Constraints:

$1 \le T \le 100$

$1 \le K \le 7$

$K \le N \le 1000$

Solution by Arjun Suresh

Complexity: $O (kn)$, but since, $k <=7$, it is fine <syntaxhighlight lang="c" name="productofkdigits">

1. include<stdio.h>
2. include<string.h>

int main() {

       char array[1001];
       int i, j, l, k, n, num;
       scanf("%d", &num);
       for(i = 0; i < num; i++)
       {
               scanf("%d%d", &n, &k);
               scanf("%s", array);
               unsigned long big = 0;
               for(j = 0; j < strlen(array)-k; j++)
               {
                       unsigned long  product = 1;
                       for(l = j; l < j+k; l++)
                               product *= array[l]-'0';
                       if(product > big)
                               big = product;
               }
               printf("%lu\n", big);
       }

}

</syntaxhighlight>

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