IOI 2010
All 7 IOI tasks from 2010, organized as individual solution pages.
Problem set
Each entry below goes straight to the public problem page, with the statement, editorial, code, and raw resources kept together.
Cluedo
This is an interactive problem modeled after the board game Cluedo. There are M murderers, W weapons, and L locations. The secret answer is a triple (m^*, w^*, l^*). In each query you guess a triple (m, w, l) and the...
Hotter Colder
An interactive problem on the integer line [1, N]. A hidden value X is fixed. Starting from position 1, each guess G receives a response: Hotter (+1): |G - X| < |P - X| where P is the previous guess. Colder (-1): |G -...
Language
Nature of the Task This is not a classical exact-algorithm task. It is an online classification problem: for each excerpt, we must guess one of 56 languages, then the grader reveals the correct answer and we may updat...
Memory
An interactive memory card game. There are 2N face-down cards forming N matching pairs. Each turn, flip two cards. If they match, they are removed. Otherwise, they are flipped back. The goal is to match all pairs usin...
Quality of Living
Given an R C grid where each cell has a unique quality rating from 1 to RC, find an H W subgrid whose median is minimized. The median of HW values is the HW/2 -th smallest value.
Saveit
Given a connected graph with N nodes (N 1000) and H hub nodes (H 36, nodes 0,, H-1), encode the shortest-path distances from every hub to every node into a bit string. The decoder must reconstruct all H N distances fr...
Traffic
Given a tree of N cities where city i has population p_i, find a city r such that when the tree is rooted at r, the maximum subtree population among r 's children is minimized. This node is called the traffic center.