@Akash: The sum of the numbers from 1 to n is S(n) = n*(n+1)/2. Thus, the sum of the numbers from a to b is S = S(b) - S(a-1) = ( b*(b+1) - a*(a-1) ) / 2.
Dave On Mar 20, 9:08 am, Akash Mukherjee <[email protected]> wrote: > Majid is a 3rd-grade elementary student and quite well in mathematics. Once, > Majid's teacher asked him to calculate the sum of numbers 1 through n. > > Majid quickly answered, and his teacher made him another challenge. He asked > Majid to calculate the sum of the digits of numbers 1 through n. > > Majid did finally find the solution. Now it is your turn, can you find a > solution? > Input > > Two space-separated integers 0 <= a <= b <= 109. > > Program terminates if a and b are -1. > Output > > The sum of the digits of numbers a through b. > Example > > *Input:* > 1 10 > 100 777 > -1 -1 > *Output:* > 46 > 8655 > > ne ideas?? -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
