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1 Definition In computer science, a topological sort or topological ordering of a directed graph is a linear ordering of its vertices such that for every directed edge uv from vertex u to vertx v, u comes before v in the ordering. It sounds pretty academic, but I am sure you are using topological sort unconsciously every single day. 2 Application Many real world situations can be modeled as a graph with directed edges where some events must occur before others....

1 前言 「最好的学习方式」 在如今打广告也需要遵守广告法的时代，用这样的标题来描述某个学习方法难免会让人觉得言过其实，不客气的朋友可能会直接说「...

1 前言 秦人不暇自哀而后人哀之，后人哀之而不鉴之，亦使后人而复哀后人也 每个朝代灭亡之后，就会由下一个朝代的史官编写，如元朝灭亡之后，就由明朝来...

1 前言 历史教科书说，与英国的第一次鸦片战争，敲开了清朝的大门，清朝也因此和外国签订了一系列不平等条约. 而因为清朝的落伍，导致清朝不敌英国. 教...

1 命运的必然 公元前219年，汉尼拨翻过阿尔卑斯山，向意大利发起进攻，指挥官科尔涅利乌斯迎战汉尼拨，被重伤。幸而从手下的新兵抢回到营地，而这名...