Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Inspired by this question (Find an integer not among four billion given ones).
How much storage space would it require to store an integer that was the summation of the numbers 1 to 4 billion?
For example, 1+2+3+4+5 = 15. Summation of 1 to 1 million = 500,000,500,000.
Here is an algorithm that may help
The function you link to describe how to find the n’th Triangular Number, which is defined as the sum of the n natural numbers from 1 to n.
Substituting 4 billion as n into the function gives 8000000002000000000.
Expressing that as a number of bits can be worked out by taking the base-2 logarithm of the value and rounding up –
ceil(log(8000000002000000000)/log(2)) = 63
So, 63 bits of storage are required.