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DIFFICULTY

CAKEWALK

PREREQUISITES

Simple Math

PROBLEM

You wish to equally distribute N candies among M people, using the following algorithm

nCandies = 0
candies-with-each-person = 0

while nCandies ≥ M
    ++candies-with-each-person
    nCandies = nCandies - M

Print the values of candies-with-each-person and nCandies at the end of the algorithm.

EXPLANATION

The given algorithm is an ad-hoc simultation of the division operation.

At the end of the algorithm, it is clear that

candies-with-each-person =
    quotient of N divided by M

and

nCandies =
    remainder of N divided by M

CODING COMMENTARY

There were two common pitfalls. The hint to both of them lay discreetly within the Constraints section.

M could be equal to 0

A lot of submissions received

Runtime Error: Floating Point Exception

verdict because of this pitfall.

The exact error of course is the attempted division by 0. Handling it as a special case is one solution.

N,M could be equal to 8,589,934,591

This typically led to a Wrong Answer verdict. The range of integers handled by the 32-bit signed integer datatype is typically

[-2147483648 2147483647]

One had to use 64-bit integer datatype to solve this problem. This means

• long long in C/C++ - as CodeChef uses the GNU C++ Compiler
• long in Java

PSEUDO CODE

Given: N, M
if M == 0
    return {
        candies-with-each-person = 0,
        nCandies = N
    }
else
    return {
        candies-with-each-person = N / M,
        nCandies = N % M
    }

Here, we assume that

• N and M are 64-bit integers
• % is the modulo operation

SETTER'S SOLUTION

Can be found here.

TESTER'S SOLUTION

Can be found here.