前几天写到bfs,看到之前写的,突然感觉不对,后来发现自己把点权值默认当成了边权值,导致一直走不出来: 点权值嘛,就是经过这个点时,要付出这么多的代价,边权值则是经过边时付出,二者有区别滴: 边权值求最短路那就是dij,bell_man之类的最短路算法楼,点权值一般就是给一个类似迷宫的图,求起点到终点的最短权值咯: 优先队列会优先push出权值最短的点,所以一旦出现终点的node一定是最短的了: 搞混之后一直认为priority求出的不一定对= =…

题目确实简单,思路很容易出来,难点在于障碍的记录,是BFS迷宫问题中很经典的题目了. POJ2935-Basic Wall Maze 题意:6*6棋盘,有三堵墙,求从给定初始点到给定终点的最短路,输出同一路长的最短路中的任一路径. 题解:BFS就不说了,对于障碍的记录,我的想法是针对每一个点都记录一次各方向上的情况.比如东边有障碍则在障碍两侧的点增加一个方向数组,用以记录左点的东侧和右点的西侧有障碍,在BFS扩展该方向时,增加一层循环判断一次该方向是否有障碍就行,时间度不会耗费很高,最坏时间度也…

/** problem: http://www.fjutacm.com/Problem.jsp?pid=3700 按二进制将k个待查点分类分别跑dijkstra **/ #include<stdio.h> #include<vector> #include<queue> using namespace std; ; ; const int INF = 0x3f3f3f3f; int ans; template <typename T> class Graph…

今天讲的BFS,不得不说,福建三中订的旅馆是真的劲,早餐极棒!!! 早上和yty大神边交流边听zld犇犇讲BFS,嘛,今天讲的比较基础,而且BFS也很好懂(三天弄过一道青铜莲花池的我好像没资格说),除了BFS,还有基本的搜索优化,但实际上并不是很清楚讲了什么?? 讲了些经典题目,可以说是很强. 下午考试,比较凉,大概可以当提高组day1第2道题和day2的1,2道题的难度?(个人感觉) T1,规律题,比今年noip的t1好写多了,题意大概就是给出k中字符的数量,判断能不能组成一个回文数,试图暴力…

题目:http://acm.hdu.edu.cn/showproblem.php?pid=1026 Problem Description The Princess has been abducted by the BEelzebub feng5166, our hero Ignatius has to rescue our pretty Princess. Now he gets into feng5166's castle. The castle is a large labyrinth.…

之前用dfs剪枝AC了,http://www.cnblogs.com/ediszhao/p/4741825.html,这次用bfs+priority_queue来尝试解题 题意:拯救行动,天使r有多个朋友a(friends,在这里被坑了几次,没看清题意),天使被关在牢房里,等着朋友来拯救,求拯救天使的最短距离. 以天使为起点进行bfs,找到的a就是最小拯救时间值. #include <iostream> #include <cstring> #include <queue&g…

连连看 如上图所示如果采用传统bfs的话,如果按照逆时针方向从(1,1)-->(3,4)搜索,会优先选择走拐四次弯的路径导致ans错误: Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 34028    Accepted Submission(s): 8438 Problem Description “连连看”相信很多人都玩过.没玩过…

Ivan's Car Time limit: 1.5 secondMemory limit: 64 MB The world is in danger! Awful earthquakes are detected all over the world. Houses are destroyed, rivers overflow the banks, it is almost impossible to move from one city to another. Some roads are…

1.CF #375 (Div. 2)  D. Lakes in Berland 2.总结:麻烦的bfs,但其实很水.. 3.题意:n*m的陆地与水泽,水泽在边界表示连通海洋.最后要剩k个湖,总要填掉多少个湖,然后输出. #include<bits/stdc++.h> #define F(i,a,b) for (int i=a;i<b;i++) #define FF(i,a,b) for (int i=a;i<=b;i++) #define mes(a,b) memset(a,b,s…

Waiting ten thousand years for Love Time Limit: 10000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1057    Accepted Submission(s): 335 Problem Description It was ten thousand years, after Demon Lemon caught Y…