Problem
Add all odd numbers from 1 up to and including n, using a loop.
Implement sum_of_odds(n).
Input
n: The upper limit.
Output
Return the sum of the odd numbers from 1 through n (0 if there are none).
Constraints
0 ≤ n ≤ 1,000,000
Examples
Example 1
Input:
n = 7
Expected output:
expected = 16Input:
long long n = 7;
Expected output:
long long expected = 16;Input:
long n = 7;
Expected output:
long expected = 16;Explanation
1 + 3 + 5 + 7 = 16.
Example 2
Input:
n = 0
Expected output:
expected = 0Input:
long long n = 0;
Expected output:
long long expected = 0;Input:
long n = 0;
Expected output:
long expected = 0;Explanation
There are no odd numbers from 1 to 0, so the sum is 0.
How to approach it
Try on your own first, then open one hint at a time.
Hint 1
Only odd numbers contribute, so skip the even ones while scanning upward.
Hint 2
A loop that steps through the sequence and adds matching values is enough.
Hint 3
If the upper limit is below 1, the total should stay zero.
Expected complexity
O(n) time, O(1) extra space
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.