Midyear Online Camp - Contest 03

02 February 2020 - 2 mins read time
Tags: Editorial

Contest link: https://codeforces.com/contests/267777

A. Amr and Even Integers

Credits: Amr Salama

This was the easiest problem in the contest. You are asked to round the division result to be even.

Note:

• ceil will always rounds the result to the upper bound ceil(2.3) = 3.
• floor will always rounds the result to the lower bound floor(3.9) = 3.
• round will rounds the result towards the nearest integer round(2.6) = 3, round(3.2) = 3.

We don’t need to use any of them, We can simply calculate the integer division and check whether it is odd or not, if it is odd then add one to the result, otherwise print the result.

B. Omar and Bike

Credits: Ismail Akram

To solve this problem you need to note input constraint (m <= n), So there is a possibility that m could be equal to n, and so Omar may not save any money at all in this case (n - m = 0), and you should print -1 in this case.

Otherwise, the result is the ceil of k / (n-m). If you didn’t check for -1 case first, you may have run time error due to division by zero.

C. Ismail’s Exams

Credits: Ismail Akram

This problem is direct implementation. First, you need to note that Ismail needs at least n/2 to pass. So read the string, count how many 1 in it, and print the difference between n/2 and the count of 1 in the string, Note this may be negative, in this case print 0 (Ismail already passed without Amr’s help).

Another C++ solution

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