1656: [Usaco2006 Jan] The Grove 树木 # Time Limit: 5 Sec Memory Limit: 64 MB Submit: 143 Solved: 88 [Submit][Status][Discuss]
Description # The pasture contains a small, contiguous grove of trees that has no ‘holes’ in the middle of the it. Bessie wonders: how far is it to walk around that grove and get back to my starting position? She’s just sure there is a way to do it by going from her start location to successive locations by walking horizontally, vertically, or diagonally and counting each move as a single step. Just looking at it, she doesn’t think you could pass ’through’ the grove on a tricky diagonal. Your job is to calculate the minimum number of steps she must take. Happily, Bessie lives on a simple world where the pasture is represented by a grid with R rows and C columns (1 <= R <= 50, 1 <= C <= 50). Here’s a typical example where ‘.’ is pasture (which Bessie may traverse), ‘X’ is the grove of trees, ‘’ represents Bessie’s start and end position, and ‘+’ marks one shortest path she can walk to circumnavigate the grove (i.e., the answer): …+… ..+X+.. .+XXX+. ..+XXX+ ..+X..+ …+++ The path shown is not the only possible shortest path; Bessie might have taken a diagonal step from her start position and achieved a similar length solution. Bessie is happy that she’s starting ‘outside’ the grove instead of in a sort of ‘harbor’ that could complicate finding the best path.
1646: [Usaco2007 Open]Catch That Cow 抓住那只牛 # Time Limit: 5 Sec Memory Limit: 64 MB Submit: 915 Solved: 441 [Submit][Status][Discuss]
Description # Farmer John has been informed of the location of a fugitive cow and wants to catch her immediately. He starts at a point N (0 <= N <= 100,000) on a number line and the cow is at a point K (0 <= K <= 100,000) on the same number line. Farmer John has two modes of transportation: walking and teleporting. * Walking: FJ can move from any point X to the points X-1 or X+1 in a single minute * Teleporting: FJ can move from any point X to the point 2*X in a single minute. If the cow, unaware of its pursuit, does not move at all, how long does it take for Farmer John to retrieve it?
1619: [Usaco2008 Nov]Guarding the Farm 保卫牧场 # Time Limit: 5 Sec Memory Limit: 64 MB Submit: 661 Solved: 292 [Submit][Status][Discuss]
Description # The farm has many hills upon which Farmer John would like to place guards to ensure the safety of his valuable milk-cows. He wonders how many guards he will need if he wishes to put one on top of each hill. He has a map supplied as a matrix of integers; the matrix has N (1 < N <= 700) rows and M (1 < M <= 700) columns. Each member of the matrix is an altitude H_ij (0 <= H_ij <= 10,000). Help him determine the number of hilltops on the map. A hilltop is one or more adjacent matrix elements of the same value surrounded exclusively by either the edge of the map or elements with a lower (smaller) altitude. Two different elements are adjacent if the magnitude of difference in their X coordinates is no greater than 1 and the magnitude of differences in their Y coordinates is also no greater than 1.
Catch him # **Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 664 Accepted Submission(s): 307 **
Problem Description
在美式足球中，四分卫负责指挥整只球队的进攻战术和跑位，以及给接球员传球的任务。四分卫是一只球队进攻组最重要的球员，而且一般身体都相对比较弱小，所以通常球队会安排5-7名大汉来保护他，其中站在四分卫前方、排成一线的5名球员称为进攻锋线，他们通常都是135公斤左右的壮汉。