<题目链接> 题目大意: 现在给你一些点,这些点之间存在一些有向边,每条边都有对应的边权,有一次机会能够使某条边的边权变为原来的1/2,求从起点到终点的最短距离. 解题分析: 分层图最短路模板题,由于最多只能将一条边变成原来的1/2,所以我们在原来二维的图形上多加一层,由第一层到第二层的边代表该边边权为原边权的1/2.就按这种思想跑一遍Dijkstra即可. #include <cstdio> #include <cstring> #include <algori…

Flight Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 2014    Accepted Submission(s): 428 Problem Description Recently, Shua Shua had a big quarrel with his GF. He is so upset that he decides…

Flight Time Limit : 20000/10000ms (Java/Other)   Memory Limit : 65535/65535K (Java/Other) Total Submission(s) : 5   Accepted Submission(s) : 1 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description Recently, Shua Shua had a big…

任意门:https://www.luogu.org/problemnew/show/P2939 Revamping Trails 题目描述 Farmer John dutifully checks on the cows every day. He traverses some of the M (1 <= M <= 50,000) trails conveniently numbered 1..M from pasture 1 all the way out to pasture N (a…

3627: [JLOI2014]路径规划 Time Limit: 30 Sec  Memory Limit: 128 MBSubmit: 186  Solved: 70[Submit][Status][Discuss] Description 相信大家都用过地图上的路径规划功能,只要输入起点终点就能找出一条最优路线.现在告诉你一张地图的信息,请你找出最优路径(即最短路径).考虑到实际情况,一辆车加满油能开的时间有限,所以在地图上增加了几个加油站. 地图由点和双向边构成,每个点代表一个路口,也有可…

Recently, Shua Shua had a big quarrel with his GF. He is so upset that he decides to take a trip to some other city to avoid meeting her. He will travel only by air and he can go to any city if there exists a flight and it can help him reduce the tot…

Description 每天,农夫John需要经过一些道路去检查牛棚N里面的牛. 农场上有M(1<=M<=50,000)条双向泥土道路,编号为1..M. 道路i连接牛棚P1_i和P2_i (1 <= P1_i <= N; 1 <= P2_i<= N). John需要T_i (1 <= T_i <= 1,000,000)时间单位用道路i从P1_i走到P2_i或者从P2_i 走到P1_i 他想更新一些路经来减少每天花在路上的时间.具体地说,他想更新K (1 &l…

Flight Recently, Shua Shua had a big quarrel with his GF. He is so upset that he decides to take a trip to some other city to avoid meeting her. He will travel only by air and he can go to any city if there exists a flight and it can help him reduce…

一开始想的并查集(我一定是脑子坏掉了),晚上听学姐讲题才知道就是dijkstra两层: 题意:有一次机会能使一条边的权值变为原来的一半,询问从s到e的最短路. 将dis数组开成二维,第一维表示从源点到点i的路径长度,第二维表示是否使用了该次机会,并以此不断更新. 用map将字符串转为int,剩下的就是dijkstra+优先队列: #include<cstdio> #include<cstring> #include<iostream> #include<map&g…

问题描述 幻想历8012年5月12日深夜,斯普林·布拉泽降下神谕:“Trust me, earn eternal life.”克里斯军团士气大增.作为克里斯军团的主帅,你决定利用这一机会发动奇袭,一举击败杰森国.具体地说,杰森国有N个城市,由M条单向道路连接.神谕镇是城市1而杰森国的首都是城市N.你只需摧毁位于杰森国首都的曾·布拉泽大神殿,杰森国的信仰,军队还有一切就都会土崩瓦解,灰飞烟灭. 为了尽量减小己方的消耗,你决定使用自爆机器人完成这一任务.唯一的困难是,杰森国的一部分城市有结界保护,不…