Choosing the Commander 题目描述As you might remember from the previous round, Vova is currently playing a strategic game known as Rage of Empires. Vova managed to build a large army, but forgot about the main person in the army 2017-06-30 OI > String #Trie Tree
Fox and Dinner 题目描述Fox Ciel is participating in a party in Prime Kingdom. There are $n$ foxes there (include Fox Ciel). The $i$-th fox is $a_i$ years old. They will have dinner around some round tables. You want to 2017-06-29 OI > Number Theory #Prime #Network Flow
Karen and Cards 题目描述Karen just got home from the supermarket, and is getting ready to go to sleep. After taking a shower and changing into her pajamas, she looked at her shelf and saw an album. Curious, she opened it 2017-06-29 OI > Data Structure #Segment Tree
Karen and Supermarket 题目描述On the way home, Karen decided to stop by the supermarket to buy some groceries. She needs to buy a lot of goods, but since she is a student her budget is still quite limited. In fact, she can onl 2017-06-25 OI > Common Skill #Dynamic Programming #Tree
Karen and Test 题目描述Karen has just arrived at school, and she has a math test today! The test is about basic addition and subtraction. Unfortunately, the teachers were too busy writing tasks for Codeforces rounds, an 2017-06-25 OI > Number Theory #Combinatorics #Multiplicative Inverse
Karen and Game 题目描述On the way to school, Karen became fixated on the puzzle game on her phone! The game is played as follows. In each level, you have a grid with $n$ rows and $m$ columns. Each cell originally contai 2017-06-25 OI > Common Skill #Greedy #Implementation
Fox and Jumping 题目描述Fox Ciel is playing a game. In this game there is an infinite long tape with cells indexed by integers (positive, negative and zero). At the beginning she is standing at the cell $0$. There are al 2017-06-24 OI > Number Theory #Dynamic Programming #GCD-LCM
Fox and Names 题目描述Fox Ciel is going to publish a paper on FOCS (Foxes Operated Computer Systems, pronounce: “Fox”). She heard a rumor: the authors list on the paper is always sorted in the lexicographical order. Af 2017-06-24 OI > Graph Theory #Topological-Sort
Shaass and Lights 题目描述There are $n$ lights aligned in a row. These lights are numbered $1$ to $n$ from left to right. Initially some of the lights are switched on. Shaass wants to switch all the lights on. At each step 2017-06-23 OI > Number Theory #Combinatorics
Shaass and Bookshelf 题目描述Shaass has $n$ books. He wants to make a bookshelf for all his books. He wants the bookshelf’s dimensions to be as small as possible. The thickness of the $i$-th book is $t_i$ and its pages’ width 2017-06-23 OI > Common Skill #Dynamic Programming #Greedy