IOI 2020

There are x bags to fill with biscuits. Biscuit type i has tastiness 2^i, and there are a[i] biscuits of type i available. Each bag must have the same total tastiness y. Count the number of distinct values of y that a...

Plants are arranged on a circle. The value r[i] describes the local ranking constraint for plant i inside the next k positions. For each query (x,y), we must decide whether every valid height assignment forces x to be...

Given an n n matrix p where p[i][j] \ 0, 1, 2, 3\, construct a simple undirected graph on n nodes such that the number of distinct simple paths between nodes i and j equals p[i][j]. If no such graph exists, report it....

There are n mushrooms, each either type A or type B. Mushroom 0 is known to be type A. You can query a function use\_machine(x) that takes a sequence of mushroom indices and returns the number of adjacent pairs in the...

Given a tree with n nodes, assign labels from \ 0, 1,, n-1\ (all distinct, but need not match node indices) such that given only the labels of the current node s and target node t, plus the sorted list of labels of s...

There are n colors and m tickets per color. Ticket j of color i has value x[i][j] (sorted in non-decreasing order within each color). There are k rounds. In each round, exactly one ticket from each color is used (each...