1242Rescue (优先队列BFS)】的更多相关文章

链接: http://acm.hdu.edu.cn/showproblem.php?pid=1026 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=29096#problem/D Ignatius and the Princess I Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(…
Rescue Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 521    Accepted Submission(s): 217   Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is d…
普通BFS:每个状态只访问一次,第一次入队时即为该状态对应的最优解. 优先队列BFS:每个状态可能被更新多次,入队多次,但是只会扩展一次,每次出队时即为改状态对应的最优解. 且对于优先队列BFS来说,每次存入队列的不光是像普通BFS的状态,还有当前状态对应的代价,并且是依据最小代价进行扩展.每次状态被更近之后,将其入队. 对于本题来说 状态选取:当前所在城市,当前油量 代价函数:当前状态所对应的最小花费 代码如下: #include <cstdio> #include <iostream…
题目链接:http://codeforces.com/problemset/problem/677/D 题意: 有 $n \times m$ 的网格,每个网格上有一个棋子,棋子种类为 $t[i][j]$,棋子的种类数为 $p$. 现在出发点为 $(1,1)$,必须按照种类 $1 \sim p$ 进行移动,即从种类 $x$ 的棋子出发,下一个目标必须是 $x+1$ 才行,直到走到种类为 $p$ 的棋子就终止.求最短路径. 题解: 我们先把棋子按照种类分组,分成 $p$ 组. $dp[i][j]$…
题目链接:http://poj.org/problem?id=2449 Time Limit: 4000MS Memory Limit: 65536K Description "Good man never makes girls wait or breaks an appointment!" said the mandarin duck father. Softly touching his little ducks' head, he told them a story. &quo…
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…
Rescue Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 25203    Accepted Submission(s): 8936 Problem Description Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is…
给你n个物品交换,每个交换用r,v,t描述,代表需要用r元的东西花费t时间交换得v元的东西.一开始只有1元的东西,让你求出交换到价值至少为m的最少时间代价.相当于每个交换是一条边,时间为边权,求走到价值大于等于m的点的最短路径.bfs的时候,用优先队列来储存状态,每次取出花费总时间最小的状态. #include<cstdio> #include<queue> #include<algorithm> #include<vector> #define ll lo…
Charitable Exchange Time Limit: 4000/2000MS (Java/Others)     Memory Limit: 65535/65535KB (Java/Others) Submit Status Have you ever heard a star charity show called Charitable Exchange? In this show, a famous star starts with a small item which value…
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…