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H. The Most Reckless Defense You are playing a very popular Tower Defense game called "Runnerfield 2". In this game, the player sets up defensive towe 阅读全文
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G. GCD on a grid Not long ago, Egor learned about the Euclidean algorithm for finding the greatest common divisor of two numbers. The greatest common 阅读全文
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D. Colored Balls There are balls of $n$ different colors; the number of balls of the $i$-th color is $a_i$. The balls can be combined into groups. Eac 阅读全文
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D. Buying Jewels Alice has $n$ coins and wants to shop at Bob's jewelry store. Today, although Bob has not set up the store yet, Bob wants to make sur 阅读全文
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C. Ticket Hoarding As the CEO of a startup company, you want to reward each of your $k$ employees with a ticket to the upcoming concert. The tickets w 阅读全文
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F. New Year Tree You are a programmer and you have a New Year Tree (not the traditional fur tree, though) — a tree of four vertices: one vertex of deg 阅读全文
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F - Oddly Similar Problem Statement There are $N$ sequences of length $M$, denoted as $A_1, A_2, \ldots, A_N$. The $i$-th sequence is represented by $ 阅读全文
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D. Non-Palindromic Substring A string $t$ is said to be $k$-good if there exists at least one substring$^\dagger$ of length $k$ which is not a palindr 阅读全文
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树上数颜色 题目描述 给一棵根为 $1$ 的树，每次询问子树颜色种类数。 输入格式 第一行一个整数 $n$，表示树的结点数。 接下来 $n-1$ 行，每行一条边。 接下来一行 $n$ 个数，表示每个结点的颜色 $c[i]$。 接下来一个数 $m$，表示询问数。 接下来 $m$ 行表示询问的子树。 输 阅读全文
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G. Shuffling Songs Vladislav has a playlist consisting of $n$ songs, numbered from $1$ to $n$. Song $i$ has genre $g_i$ and writer $w_i$. He wants to 阅读全文