include的背后是微不足道的开始

刷华为的机试题（传送门：数独），刷到了一个关于数独的题目，以为数独还有什么特殊的解，自己写了个减枝的dfs过了83%的数据，但是好多同学都有同样的问题，估计使题目的问题把，这题有多解但是做法不同，就有不同的答案，但是答案都是正确的，然后test有只有一个这就很恼火，所以就假装我这是正确的吧。 以前听说过数独但是一直没有深入学习过，今天借着刷题学习了一下关于数独的知识，想不到什么高效的解法，就...

  D. Sleepy Gametime limit per test2 secondsmemory limit per test256 megabytesPetya and Vasya arranged a game. The game runs by the following rules. Players have a directed graph consisting of n verti...

F. Berland and the Shortest Pathstime limit per test5 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputThere are nn cities in Berland. Some pairs of cities are connecte...

D. GCD Counting time limit per test 4.5 seconds memory limit per test 256 megabytes input standard input output standard output You are given a tree consisting of nn vertices. A number is wri...