https://adnatull.github.io/tags/binary-search/Recent content in Binary Search on Adnatull's Bloghttps://adnatull.github.io/images/logo.jpghttps://adnatull.github.io/images/logo.jpgHugoen-usMon, 29 Jan 2018 13:23:00 +0000https://adnatull.github.io/dev/2018/01/29/uva-11876-n--nod-n/Mon, 29 Jan 2018 13:23:00 +0000https://adnatull.github.io/dev/2018/01/29/uva-11876-n--nod-n/<h3 id="description">Description:</h3> <p>For a number N, first have to calculate N-1+divisors(N-1) &amp; store it in array (e.g. arr[i]=arr[i-1]+divisors(arr[i-1])). Make a sequence from 1 to until arr[i] becomes greater than 1000000. Then you will be given two numbers A &amp; B, and you will have to find the number of integers from the above sequence which lies within the range [A,B].</p> <p>Hints = No critical case. Easy problem.</p> <!-- more --> <h3 id="algorithm">Algorithm:</h3> <p>Step 1: First find the prime numbers from 1 to 1000000 and store them in an array (was not sure about the range, thats why I calculated till 1000000) . Step 2: Calculate number of divisors for each numbers from 1 to 1000000 and store divisors in each array. (e.g. divisors of 6 are 1,2,3,6. Total 4 divisors. So divisor[6]=4. ) Step 3: To find the divisors of each number, I took help of prime numbers. There is a good tutorial in lightoj.com to find divisors using primes. Link is give below: <a href="http://lightoj.com/article_show.php?article=1003">http://lightoj.com/article_show.php?article=1003</a></p>