28. Sum of First N Natural Numbers
Foundation1000 ms256 MBSolved by 0%
Read an integer n and print the sum of the first n natural numbers:
1 + 2 + 3 + ... + n
Constraints - `1 ≤ n ≤ 1000000`
Input
A single line containing one integer n.
Output
Print one integer, the sum from 1 to n.
Input10
Output55
Noteis a small case you can check by hand
Input1
Output1
Noteis the smallest input, where the answer is n itself
Hints
Four rungs, in order. The last two open once you have submitted an attempt. A wrong one counts.
Hint 1Where to start
Hint 2The approachOpen hint 1 first. This one carries on from it.
Hint 3PseudocodeOpen hint 2 first. This one carries on from it.
Hint 4Full solutionOpen hint 3 first. This one carries on from it.