POJ 1556 - The Doors题意:    在 10x10 的空间里有很多垂直的墙,不能穿墙,问你从(0,5) 到 (10,5)的最短距离是多少.    分析:        要么直达,要么一定是墙的边缘点之间以及起始点.终点的连线.        所以先枚举墙上每一点到其他点的直线可达距离,就是要判定该线段是否与墙相交(不含端点).        然后最短路. #include <iostream> #include <cstdio> #include <cmat…

LINK 题意:在$10*10$的几何平面内,给出n条垂直x轴的线,且在线上开了两个口,起点为$(0, 5)$,终点为$(10, 5)$,问起点到终点不与其他线段相交的情况下的最小距离. 思路:将每个开口的两端点作为一个节点,再枚举点与点间能否直接到达(判相交),以此建图求最短路. /** @Date : 2017-07-11 16:17:31 * @FileName: POJ 1556 线段交+dijkstra 计算几何.cpp * @Platform: Windows * @Author :…

http://poj.org/problem?id=1556 首先路径的每条线段一定是端点之间的连线.证明?这是个坑...反正我是随便画了一下图然后就写了.. 然后re是什么节奏?我记得我开够了啊...然后再开大点才a...好囧啊. #include <cstdio> #include <cstring> #include <cmath> #include <string> #include <iostream> #include <alg…

题目链接:http://poj.org/problem?id=1556 Time Limit: 1000MS Memory Limit: 10000K Description You are to find the length of the shortest path through a chamber containing obstructing walls. The chamber will always have sides at x = 0, x = 10, y = 0, and y…

The Doors Time Limit: 1000 MS Memory Limit: 10000 KB 64-bit integer IO format: %I64d , %I64u   Java class name: Main [Submit] [Status] [Discuss] Description You are to find the length of the shortest path through a chamber containing obstructing wall…

思路:暴力判断每个点连成的线段是否被墙挡住,构建图.求最短路. 思路很简单,但是实现比较复杂,模版一定要可靠. #include<stdio.h> #include<string.h> #include<math.h> #include<iostream> using namespace std; ,M=N*N; const double INF=0x3f3f3f3f; ; int sgn(double x){ ; ) ; ; } struct point{…

题意: 给一个正方形,从左边界的中点走到右边界的中点,中间有一些墙,问最短的距离是多少. 解法: 将起点,终点和所有墙的接触到空地的点存下来,然后两两之间如果没有线段(墙)阻隔,就建边,最后跑一个最短路SPFA,即可得出答案. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> #include <a…

The Doors Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 5210   Accepted: 2124 Description You are to find the length of the shortest path through a chamber containing obstructing walls. The chamber will always have sides at x = 0, x =…

  The Doors Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 7430   Accepted: 2915 Description You are to find the length of the shortest path through a chamber containing obstructing walls. The chamber will always have sides at x = 0, x…

The Doors Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 6734   Accepted: 2670 Description You are to find the length of the shortest path through a chamber containing obstructing walls. The chamber will always have sides at x = 0, x =…