解题心得: 1.读清楚题意,本题的题意是有多个'r'(起点),多个r多个bfs比较最短的时间即可,但是hdoj的数据比较水,直接一个起点就行了,迷宫里有多个守卫,如果在路途中遇到守卫会多花费一个时间点,求最短时间救到公主. 2.(解法一)因为遇到守卫会多花费一个时间,所以在守卫的地方再次压入,但是时间加一,这样就可以让队列里面的先验证. 3.之前将此题理解为要将所有的守卫打败之后,才能救到天使,之前题意理解错误用了回溯法,找出所有打败全部守卫的情况,找到最短的路径.此题的数据0<n<m<…

Rescue Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 12927    Accepted Submission(s): 4733 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is d…

题目链接:hdu 1242 这题也是迷宫类搜索,题意说的是 'a' 表示被拯救的人,'r' 表示搜救者(注意可能有多个),'.' 表示道路(耗费一单位时间通过),'#' 表示墙壁,'x' 代表警卫(耗费两个单位时间通过),然后求出 'r' 能找到 'a' 的最短时间,找不到输出 "…………"(竟然在这里也 wa 了一发 -.-||).很明显是广搜了,因为 'r' 可能有多个,所以我们反过来从 'a' 开始搜,每次搜到 'r' 都更新最小时间值(很重要的一个转换!).可是这题因为通过 '…

看题传送门: ZOJ http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1649 HDU http://acm.hdu.edu.cn/showproblem.php?pid=1242 题目大意初始位置在r,要求到达a的地点,地图上"."通过需要1s,"x"代表守卫,通过耗时2s,"#"不能走. BFS的应用. BFS求最短路径的原理是每一次向外扩张一格,(就像树的层次遍历一样…

Rescue Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other) Total Submission(s) : 14   Accepted Submission(s) : 7 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description Angel was caught by the MOLIGPY…

http://acm.hdu.edu.cn/showproblem.php?pid=1242 感觉题目没有表述清楚,angel的朋友应该不一定只有一个,那么正解就是a去搜索r,再用普通的bfs就能过了. 但是别人说要用优先队列来保证时间最优,我倒是没明白,步数最优跟时间最优不是等价的吗?就算士兵要花费额外时间,可是既然先到了目标点那时间不也一定是最小的? 当然用优先队列+ a去搜索r是最稳妥的. #include <cstdio> #include <cstring> #inclu…

此刻再看优先队列,不像刚接触时的那般迷茫!这也许就是集训的成果吧! 加油!!!优先队列必须要搞定的! 这道题意很简单!自己定义优先级别! +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ =================================================================================== +++++++++++++…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=1242 题目描述: Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison…

题目链接:Rescue 进度落下的太多了,哎╮(╯▽╰)╭,渣渣我总是埋怨进度比别人慢...为什么不试着改变一下捏.... 開始以为是水题,想敲一下练手的,后来发现并非一个简单的搜索题,BFS做肯定出事...后来发现题目里面也有坑 题意是从r到a的最短距离,"."相当时间单位1,"x"相当时间单位2,求最短时间 HDU 搜索课件上说,这题和HDU1010相似,刚開始并没有认为像剪枝,就改用  双向BFS   0ms  一Y,爽! 网上查了一下,神牛们居然用BFS+优…

Rescue Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 12441 Accepted Submission(s): 4551 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is descri…

题目链接 ZOJ链接 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task…

第一次用容器做的BFS题目,题目有个地方比较坑,就是遍历时的方向,比如上下左右能AC,右上左下就WA #include <stdio.h> #include <string.h> #include <iostream> #include <queue> using namespace std; char map[205][205]; int x_begin,y_begin,flag,n,m; int v[205][205],d[4][2] = { {-1,0…

题目 /******************以下思路来自百度菜鸟的程序人生*********************/ bfs即可,可能有多个’r’,而’a’只有一个,从’a’开始搜,找到的第一个’r’即为所求 需要注意的是这题宽搜时存在障碍物,遇到’x’点是,时间+2,如果用普通的队列就 并不能保证每次出队的是时间最小的元素,所以要用优先队列,第一次用优先队列,还不熟练哇 优先队列(priority_queue)的基本操作: empty(); 队列为空返回1 pop();   出队 push(…

Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task is: approa…

题意:X代表卫兵,a代表终点,r代表起始点,.代表路,#代表墙,走过.要花费一秒,走过x要花费2秒,求从起点到终点的最少时间. 析:一看到样例就知道是BFS了吧,很明显是最短路径问题,不过又加了一个条件——时间,所以我们用优先队列去优先获取时间短的路径,总体实现起来没有太大难度. 代码如下: #include <iostream> #include <cstdio> #include <vector> #include <set> #include <…

题目来源: http://acm.hdu.edu.cn/showproblem.php?pid=1242 题目描述: Problem Description   Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the pris…

http://acm.hdu.edu.cn/showproblem.php?pid=1242 问题:牢房里有墙(#),警卫(x)和道路( . ),天使被关在牢房里位置为a,你的位置在r处,杀死一个警卫要一秒钟,每走一步要一秒钟,求最短时间救出天使,不能救出则输出:Poor ANGEL has to stay in the prison all his life.  求最短路径,果断广搜BFS 限制及剪枝: 1.墙不能走,不能离开牢房范围 2.杀死一个警卫要多花一秒钟 3.当前步骤大于等于最短时间…

题意: 一个天使a被关在迷宫里,她的很多小伙伴r打算去救她.求小伙伴就到她须要的最小时间.在迷宫里有守卫.打败守卫须要一个单位时间.假设碰到守卫必须要杀死他 思路: 天使仅仅有一个,她的小伙伴有非常多,所以能够让天使找她的小伙伴,一旦找到小伙伴就renturn.时间小的优先级高.优先队列搞定 #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include&l…

Rescue Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 24205    Accepted Submission(s): 8537 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is d…

Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task is: approa…

题目链接 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task is: a…

题目传送门 题意:从r走到a,遇到x多走一步,问最小走到a的步数 分析:因为r有多个,反过来想从a走到某个r的最小步数,简单的BFS.我对这题有特殊的感情,去年刚来集训队时肉鸽推荐了这题,当时什么都不会,看个数组模拟队列的BFS看的头晕,现在看起来也不过如此,额,当年开始是从r走到a的,因为数据巨弱才过的,应该要用到优先队列. /************************************************ * Author :Running_Time * Created Ti…

Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task is: approach Angel…

[HDU 3712] Fiolki (带边权并查集+启发式合并) 题面 化学家吉丽想要配置一种神奇的药水来拯救世界. 吉丽有n种不同的液体物质,和n个药瓶(均从1到n编号).初始时,第i个瓶内装着g[i]克的第i种物质.吉丽需要执行一定的步骤来配置药水,第i个步骤是将第a[i]个瓶子内的所有液体倒入第b[i]个瓶子,此后第a[i]个瓶子不会再被用到.瓶子的容量可以视作是无限的. 吉丽知道某几对液体物质在一起时会发生反应产生沉淀,具体反应是1克c[i]物质和1克d[i]物质生成2克沉淀,一直进行直…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=1242 题目大意:多个起点到一个终点,普通点耗时1,特殊点耗时2,求到达终点的最少耗时. 解题思路: 如果没有特殊点,就是普通BFS. 由于特殊点的介入,所以BFS树的同一深度,各个点的值可能不同.所以使用优先队列,先取出值小的搜. 搜到的第一个符合条件的结果肯定是最小的,break. 注意有多个起点,所以先记录下所有起点,依次BFS找最小. #include "cstdio" #incl…

Rescue Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 29263    Accepted Submission(s): 10342 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is…

Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison. Angel's friends want to save Angel. Their task is: approa…

找到朋友的最短时间 Sample Input7 8#.#####. //#不能走 a起点 x守卫 r朋友#.a#..r. //r可能不止一个#..#x.....#..#.##...##...#.............. Sample Output13 bfs+优先队列 #include <iostream> #include <cstring> #include <cstdio> #include <queue> using namespace std;…

题目链接:pid=2102">传送门 题意: 三维的一个迷宫,起点在第一层的S(0,0,0)处,问是否能在规定的时间内走到第二层的P 处.'*'代表不能走,'.'代表能够走,'#'代表传送门,这里有一个trick,走到传送门的时 候必需要传送.之前没有注意到WA了非常多遍. 并且在初始的时候能够对地图进行一下处理,('*','#'),('#','*'),('#','#')这种肯定 是不能够走的,所以能够把他们都变成'*' 代码例如以下: #include <iostream>…

题意:有两只鬼,一个男孩女孩被困在迷宫中,男孩每秒可以走三步,女孩只能1步,鬼可以两步且可以通过墙.问男孩女孩是否可以在鬼抓住他们之前会合? 注意:每秒开始鬼先移动,然后两人开始移动. 思路:以男孩和女孩为起点进行双向bfs,鬼由于可以穿墙可以直接通过曼哈顿距离判断当前位置是否合法.注意在处理男孩移动的时,必须加入一点技巧,否则处理状态太多就会超时.我用的一种比较笨的方法处理男孩的移动结果TLE了. AC代码: 405ms #include<cstdio> #include<cstrin…