摘要： The pH scale measures the concentration of protons (H +) in a solution and, therefore, its acidity or alkalinity. The pH value of a solution is a numb 阅读全文

摘要： 曾经，Lele和他姐姐最喜欢，玩得最久的游戏就是俄罗斯方块(Tetris)了。 渐渐得，Lele发觉，玩这个游戏只需要手快而已，几乎不用经过大脑思考。 所以，Lele想出一个新的玩法。 Lele和姐姐先拿出一块长方形的棋盘，这个棋盘有些格子是不可用的，剩下的都是可用的。Lele和姐姐拿出俄罗斯方块里 阅读全文

摘要： A tournament is a directed graph without self-loops in which every pair of vertexes is connected by exactly one directed edge. That is, for any two ve 阅读全文

摘要： The contest’s message distribution is a big thing in prepare. Assuming N students stand in a row, from the row-head start transmit message, each perso 阅读全文

摘要： Friend HDU - 1719 Friend number are defined recursively as follows. (1) numbers 1 and 2 are friend number; (2) if a and b are friend numbers, so is ab 阅读全文

摘要： A - QQpet exploratory park HDU - 1493 Today, more and more people begin to raise a QQpet. You can get a lot of pleasure from it, although it does not 阅读全文