题解里面的翻译

P2895 [USACO08FEB] Meteor Shower S

xyx_xcc @ 2017-08-15 13:14:57

关于这道题的翻译:根据预报,一共有M颗流星(1 <= M <= 50,000)会坠落在农场上,其中第i颗流星会在时刻T_i (0 <= T_i <= 1,000)砸在坐标为(X_i, Y_i) (0 <= X_i <= 300;0 <= Y_i <= 300)的格子里。流星的力量会将它所在的格子,以及周围4个相邻的格子都化为焦土,当然贝茜也无法再在这些格子上行走。

贝茜在时刻0开始行动,它只能在第一象限中,平行于坐标轴行动,每1个时刻中,她能移动到相邻的(一般是4个)格子中的任意一个,当然目标格子要没有被烧焦才行。如果一个格子在时刻t被流星撞击或烧焦,那么贝茜只能在t之前的时刻在这个格子里出现。

请你计算一下,贝茜最少需要多少时间才能到达一个安全的格子。

每次走到某个点的时候判断是否可走有一些麻烦,我们可以预处理出一个Map数组来表示该格点在Map[i][j]之后即为不可走。然后进行正常的广搜即可。


by Hammer_cwz_77 @ 2017-08-15 14:38:44

请删掉你的帖子,否则你将接受致命性打击

@我为saber上大师


by xyx_xcc @ 2017-08-15 14:53:07

@神犇(cwz) 你傻啊?


by Hammer_cwz_77 @ 2017-08-15 15:54:18

@我为saber上大师 猪皮?


by xyx_xcc @ 2017-08-15 16:08:00

@神犇(cwz) 你是真傻


by Hammer_cwz_77 @ 2017-08-15 17:03:31

@我为saber上大师 你就是个巨神


by 田田 @ 2018-01-07 11:11:13

哈哈


by 田田 @ 2018-01-07 11:11:34

@田田


by Microsoftmonkey @ 2018-05-18 20:39:23

Bessie hears that an extraordinary meteor shower is coming; reports say that these meteors will crash into earth and destroy anything they hit. Anxious for her safety, she vows to find her way to a safe location (one that is never destroyed by a meteor) . She is currently grazing at the origin in the coordinate plane and wants to move to a new, safer location while avoiding being destroyed by meteors along her way.

The reports say that M meteors (1 ≤ M ≤ 50,000) will strike, with meteor i will striking point (Xi, Yi) (0 ≤ Xi ≤ 300; 0 ≤ Yi ≤ 300) at time Ti (0 ≤ Ti ≤ 1,000). Each meteor destroys the point that it strikes and also the four rectilinearly adjacent lattice points.

Bessie leaves the origin at time 0 and can travel in the first quadrant and parallel to the axes at the rate of one distance unit per second to any of the (often 4) adjacent rectilinear points that are not yet destroyed by a meteor. She cannot be located on a point at any time greater than or equal to the time it is destroyed).

Determine the minimum time it takes Bessie to get to a safe place

贝西听说一场非凡的流星雨即将来临;有报道称这些流星将撞击地球并摧毁任何它们击中的物体。出于对她安全的担心,她发誓要找到一条安全的地方(一个永远不会被流星摧毁的地方)。她目前正在坐标平面上吃草,想要搬到一个新的、更安全的地方,同时避免在途中被流星摧毁。 报道称,流星(1万5万)将会撞击,流星将击中点(Xi,Yi)(0 Xi 300;0 Yi 300)在时间Ti(0 Ti 1000)。每颗流星摧毁了它撞击的点,也破坏了四个直线相邻的晶格点。 贝西在0时刻离开原点,可以在第一象限,以每秒钟一个距离单位的速度与坐标轴平行,到任何一个(通常是4)相邻的直线点,它们还没有被流星摧毁。在任何时候,她都不能被定位在一个点上,大于或等于它被摧毁的时间)。 确定贝茜到达安全地点的最短时间。


by Microsoftmonkey @ 2018-05-18 20:39:36

机翻


by Low_key_smile @ 2022-04-17 21:09:28


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