5.1. The problem statement

The format

In general IOI-style problems have most of the following sections:

It is standard practice to theme problems in some way. For example, the USACO always sets problems about Farmer John and his cows, while recent SACOs have used a Monty Python theme. This serves to make the problem more interesting, but more importantly it allows the problem to be explained without the use of technical terms.

General advice


Graph theory problems have a whole set of common pitfalls for the problem designer. Always consider the items on this checklist and if appropriate, add information to your problem statement.

There are also some variations on what a "path" may be:


Just as with graph theory, geometry has a host of special cases that sometimes need to be considered and clarified:

Another issue with geometry is that the distance between two points is seldom an integer. This can present problems because the rounding error in floating point arithmetic may cause a perfectly valid algorithm to produce incorrect answers. Try to avoid using distances, especially comparing distances (for example, finding the shortest path). An alternative is to define a different distance function, such as the Manhattan distance (delta x plus delta y) which will always be an integer.

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Last updated Mon Jun 19 17:54:25.0000000000 2006. Copyright Bruce Merry (bmerry '@' gmail dot. com).