POJ subway 600K 0MS 题意:乘坐地铁从家到学校,地铁40km/h 步行10km/h , 已知各个站点的x,y坐标,输入的信息每个列次用-,-1隔开,要求花费的时间最少 解决方案:把家和学校各看成一个站点,求出相邻站点的权值(路程/速度),以站点数量建立map,保留两站之间的距离,然后dijsktra算法寻找两站点间最短路径 问题:结束条件EOF,sign初始值 #include<iostream> #include<cmath> #define MAX 10000…

做这道题的动机就是想练习一下堆的应用,顺便补一下好久没看的图论算法. Dijkstra算法概述 //从0出发的单源最短路 dis[][] = {INF} ReadMap(dis); for i = 0 -> n - 1 d[i] = dis[0][i] while u = GetNearest(1 .. n - 1, !been[]) been[u] = 1 for_each edge from u d[edge.v] = min(d[edge.v], d[u] + dis[u][edge.v]…

POJ 2502 Subway / NBUT 1440 Subway / SCU 2186 Subway(图论,最短距离) Description You have just moved from a quiet Waterloo neighbourhood to a big, noisy city. Instead of getting to ride your bike to school every day, you now get to walk and take the subway.…

题目链接: http://poj.org/problem?id=2502 题目大意: 你刚从一个安静的小镇搬到一个吵闹的大城市,所以你不能再骑自行车去上学了,只能乘坐地铁或者步行去上学.因为你不想迟到,所以你想知道自己多长时间能到达学校,你步行的速度是 10km/h, 地铁的速度是40km/h, 假如你是幸运的,你刚到地铁就有一辆地铁行驶过来, 你马上就可以乘坐, 任意的一个地铁你可以乘坐多次,若果你愿意你可以换乘不同的地铁,所有的地铁都是两个方向的. 输入: 输入首先包含两个坐标,表示你家的坐…

Subway Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6692   Accepted: 2177 Description You have just moved from a quiet Waterloo neighbourhood to a big, noisy city. Instead of getting to ride your bike to school every day, you now get…

Subway Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6689   Accepted: 2176 Description You have just moved from a quiet Waterloo neighbourhood to a big, noisy city. Instead of getting to ride your bike to school every day, you now get…

http://poj.org/problem?id=2502 同一条地铁线上的站点相邻点间按照v2建边,然后所有点之间按照v1更新建边,所有的边都是双向边,both directions. 然后直接跑dij就好了,防止因为重复的站点多建了同样的点,把上限开到了500,AC. 一个小bug是因为数组开了500,然后初始化时访问了500导致越界,,,把其他位置的地址更改了检查了半天,衰,以后还是多开几十好点. #include<iostream> #include<cstdio> #i…

dij部分还是跟模板差不多的 但是这题的难点是处理输入 或者说理解题意 事实上每个点之间都是可以走的......WA了好几发就因为没意识到同一条路线上的各个站点之间居然也可以走得比车子快.... PS: POJ的C++编译器居然没法自动识别sqrt函数用哪个=.= #include <iostream> #include <string> #include <cstdio> #include <cmath> #include <cstring>…

Subway Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 4928   Accepted: 1602 Description You have just moved from a quiet Waterloo neighbourhood to a big, noisy city. Instead of getting to ride your bike to school every day, you now get…

题目传送门 题意:列车上行驶40, 其余走路速度10.问从家到学校的最短时间 分析:关键是建图:相邻站点的速度是40,否则都可以走路10的速度.读入数据也很变态. #include <cstdio> #include <cmath> #include <algorithm> #include <cstring> #include <queue> using namespace std; const int N = 2e2 + 5; const i…