Internet Problem Solving Contest

IPSC 2007

Solution to Problem A – Anti-Blot System

This task was very simple. In the easy input the blot always covered an entire number. If this number was the result, it could be computed by adding the two numbers on the left hand side. In all other cases the missing number could be computed by subtracting the known number on the left hand side from the result.

In the hard input the blot was covering only a part of the number. However, this is not really harder, we may simply discard the entire number with the blot and compute it in the same way as in the easy input.