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在2*N的一个长方形方格中，用一个1*2的骨牌排满方格。 问有多少种不同的排列方法。 例如：2 * 3的方格，共有3种不同的排法。（由于方案的数量巨大，只输出 Mod 10^9 + 7 的结果） 在2*N的一个长方形方格中，用一个1*2的骨牌排满方格。 问有多少种不同的排列方法。 例如：2 * 3的 阅读全文
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There are n pictures delivered for the new exhibition. The i-th painting has beauty ai. We know that a visitor becomes happy every time he passes from 阅读全文
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A square number is an integer number whose square root is also an integer. For example 1, 4, 81 are some square numbers. Given two numbers a and b you 阅读全文
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Solve the equation: p ∗ e −x + q ∗ sin(x) + r ∗ cos(x) + s ∗ tan(x) + t ∗ x 2 + u = 0 where 0 ≤ x ≤ 1. Input Input consists of multiple test cases and 阅读全文
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A palindrome is a word, number, or phrase that reads the same forwards as backwards. For example, the name “anna” is a palindrome. Numbers can also be 阅读全文
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It has been said that a watch that is stopped keeps better time than one that loses 1 second per day. The one that is stopped reads the correct time t 阅读全文
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Watchmen are in a danger and Doctor Manhattan together with his friend Daniel Dreiberg should warn them as soon as possible. There are n watchmen on a 阅读全文
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The Robot Moving Institute is using a robot in their local store to transport different items. Of course the robot should spend only the minimum time 阅读全文
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There is an old stone game.At the beginning of the game the player picks n(1<=n<=50000) piles of stones in a line. The goal is to merge the stones in 阅读全文
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Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a ne 阅读全文
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湫湫减肥 越减越肥！ 最近，减肥失败的湫湫为发泄心中郁闷，在玩一个消灭免子的游戏。 游戏规则很简单，用箭杀死免子即可。 箭是一种消耗品，已知有M种不同类型的箭可以选择，并且每种箭都会对兔子造成伤害，对应的伤害值分别为Di（1 <= i <= M），每种箭需要一定的QQ币购买。 假设每种箭只能使用一次 阅读全文
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Each New Year Timofey and his friends cut down a tree of n vertices and bring it home. After that they paint all the n its vertices, so that the i-th 阅读全文