Longest Prefix
IOI’96
The structure of some biological objects is represented by the sequence of their constituents denoted by uppercase letters. Biologists are interested in decomposing a long sequence into shorter ones called primitives.
We say that a sequen[……]
Zero Sum
Consider the sequence of digits from 1 through N (where N=9) in increasing order: 1 2 3 … N.
Now insert either a ‘+’ for addition or a ‘-‘ for subtraction or a ‘ ‘ [blank] to run the digits together between each pair of digits (not in front of the f[……]
Farmer John is considering purchasing a new herd of cows. In this new herd, each mother cow gives birth to two children. The relationships among the cows can easily be represented by one or more binary trees with a total of N (3 <= N < 200) nodes. The tr[……]
Money Systems
The cows have not only created their own government but they have chosen to create their own money system. In their own rebellious way, they are curious about values of coinage. Traditionally, coins come in values like 1, 5, 10, 20 or 25, 50, and[……]
Broken Necklace
You have a necklace of N red, white, or blue beads (3<=N<=350) some of which are red, others blue, and others white, arranged at random. Here are two examples for n=29:
&nb[……]
Controlling Companies
Some companies are partial owners of other companies because they have acquired part of their total shares of stock. For example, Ford owns 12% of Mazda. It is said that a company A controls company B if at least one of the following co[......]The Tamworth Two
BIO \'98 - Richard Forster
A pair of cows is loose somewhere in the forest. Farmer John is lending his expertise to their capture. Your task is to model their behavior.
The chase takes place on a 10 by 10 planar grid. Squares can be e[......]Cow Tours
Farmer John has a number of pastures on his farm. Cow paths connect some pastures with certain other pastures, forming a field. But, at the present time, you can find at least two pastures that cannot be connected by any sequence of cow paths, thus[......]USACO 2.4 Overfencing 穿越栅栏
Overfencing
Kolstad and Schrijvers
Farmer John went crazy and created a huge maze of fences out in a field. Happily, he left out two fence segments on the edges, and thus created two exits for the maze. Even more happily, the maze[......]USACO 2.2 Subset Sums集合
For many sets of consecutive integers from 1 through N (1 <= N <= 39), one can partition the set into two sets whose sums are identical.
For example, if N=3, one can partition the set {1, 2, 3} in one way so that the sums of both[……]