P2895 [USACO08FEB]流星雨Meteor Shower 题目描述 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 locatio…

题目描述 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…

题目描述 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…

一起来看流星雨吧(话说我还没看到过流星雨呢) 题目 Problem 小A则听说另一个骇人听闻的消息: 一场流星雨即将袭击整个霸中,由于流星体积过大,它们无法在撞击到地面前燃烧殆尽,届时将会对它撞到的一切东西造成毁灭性的打击. 很自然地,小A开始担心自己的安全问题.他一定要在被流星砸到前,到达一个安全的地方(也就是说,一块不会被任何流星砸到的土地). 如果将霸中放入一个直角坐标系中,小A现在的位置是原点,并且小A不能踏上一块被流星砸过的土地.根据预报,一共有M颗流星(1 \le M \le 50,…

P2895 [USACO08FEB]流星雨Meteor Shower 给每个点标记一下能够走的最迟时间,蓝后bfs处理一下 #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cctype> #include<queue> #define re register using namespace std; void read…

传送门 预处理出每个位置最早被摧毁的时间,在此之前都可以走 直接dfs加个记忆化和最优性剪枝就好了 一定要注意流星的边界,如果波及到负数坐标的位置不要去考虑会RE 一定要考虑流星砸到边界的情况 如 (300,300) 那么(300,301) 和 (301,300) 的位置都会被波及不安全,也要考虑到 注意奶牛可以跑出边界!比如(301,300) 代码简单,就不注释了 #include<iostream> #include<cstdio> #include<algorithm&…

题意:你刚开始位于坐标轴的\((0,0)\)点,一共有\(m\)颗流星砸向地面,每颗流星在\(t\)时砸到\((x,y)\)点,其四周上下左右也均有波及,你每秒可以向上下左右移动一个单位,问你是否可以移动到安全的地方(没有被流星波及的点),求最小步数. 题解:这题细节有点多,但也是一个基本的bfs,首先我们要用一个数组来记录流星砸向地面的最早时间,然后还要注意你在跑到某个点的时候可能被砸中,然后搞个结构体直接bfs,当找到某个点没有被存时间的数组记录,直接输出即可. 代码: #include <…

P2894 [USACO08FEB]酒店Hotel https://www.luogu.org/problem/show?pid=2894 题目描述 The cows are journeying north to Thunder Bay in Canada to gain cultural enrichment and enjoy a vacation on the sunny shores of Lake Superior. Bessie, ever the competent travel…

P2894 [USACO08FEB]酒店Hotel 题目描述 The cows are journeying north to Thunder Bay in Canada to gain cultural enrichment and enjoy a vacation on the sunny shores of Lake Superior. Bessie, ever the competent travel agent, has named the Bullmoose Hotel on fam…

P2894 [USACO08FEB]酒店Hotel 题目描述 The cows are journeying north to Thunder Bay in Canada to gain cultural enrichment and enjoy a vacation on the sunny shores of Lake Superior. Bessie, ever the competent travel agent, has named the Bullmoose Hotel on fam…