标签: DFS

二分图

50 years, 50 colors(HDOJ 1498)

On Octorber 21st, HDU 50-year-celebration, 50-color balloons floating around the campus, it's so nice, isn't it? To celebrate this meaningful day, the ACM team of HDU hold some fuuny games. Especially, there will be a game named "crashing color balloons".

There will be a n*n matrix board on the ground, and each grid will have a color balloon in it.And the color of the ballon will be in the range of [1, 50].After the referee shouts "go!",you can begin to crash the balloons.Every time you can only choose one kind of balloon to crash, we define that the two balloons with the same color belong to the same kind.What's more, each time you can only choose a single row or column of balloon, and crash the balloons that with the color you had chosen. Of course, a lot of students are waiting to play this game, so we just give every student k times to crash the balloons.

二分图

棋盘游戏(HDOJ 1281)

小希和Gardon在玩一个游戏:对一个N*M的棋盘,在格子里放尽量多的一些国际象棋里面的“车”,并且使得他们不能互相攻击,这当然很简单,但是Gardon限制了只有某些格子才可以放,小希还是很轻松的解决了这个问题(见下图)注意不能放车的地方不影响车的互相攻击。
所以现在Gardon想让小希来解决一个更难的问题,在保证尽量多的“车”的前提下,棋盘里有些格子是可以避开的,也就是说,不在这些格子上放车,也可以保证尽量多的“车”被放下。但是某些格子若不放子,就无法保证放尽量多的“车”,这样的格子被称做重要点。Gardon想让小希算出有多少个这样的重要点,你能解决这个问题么?

最大团

All Friends(POJ 2989)

Sociologists are interested in the phenomenon of "friendship". To study this property, they analyze various groups of people. For each two persons in such a group they determine whether they are friends (it is assumed that this relation is symmetric). The sociologists are mostly interested in the sets of friends. The set S of people is the set of friends if every two persons in S are friends. However, studying the sets of friends turns out to be quite complicated, since there are too many such sets. Therefore, they concentrate just on the maximal sets of friends. A set of friends S is maximal if every person that does not belong to S is not a friend with someone in S.

搜索

变形课(HDOJ 1181)

呃......变形课上Harry碰到了一点小麻烦,因为他并不像Hermione那样能够记住所有的咒语而随意的将一个棒球变成刺猬什么的,但是他发现了变形咒语的一个统一规律:如果咒语是以a开头b结尾的一个单词,那么它的作用就恰好是使A物体变成B物体.
Harry已经将他所会的所有咒语都列成了一个表,他想让你帮忙计算一下他是否能完成老师的作业,将一个B(ball)变成一个M(Mouse),你知道,如果他自己不能完成的话,他就只好向Hermione请教,并且被迫听一大堆好好学习的道理.

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