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 :…

#include <iostream> #include <stdio.h> #include <string.h> #include <algorithm> #include <queue> #include <map> #include <vector> #include <set> #include <string> #include <math.h> using namespac…

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…

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 =…

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 =…

LINK 题意:询问是否存在直线,使得所有线段在其上的投影拥有公共点 思路:如果投影拥有公共区域,那么从投影的公共区域作垂线,显然能够与所有线段相交,那么题目转换为询问是否存在直线与所有线段相交.判断相交先求叉积再用跨立实验.枚举每个线段的起始结束点作为直线起点终点遍历即可. /** @Date : 2017-07-12 14:35:44 * @FileName: POJ 3304 基础线段交判断.cpp * @Platform: Windows * @Author : Lweleth (Sou…

题目传送门 题意:从(0, 5)走到(10, 5),中间有一些门,走的路是直线,问最短的距离 分析:关键是建图,可以保存所有的点,两点连通的条件是线段和中间的线段都不相交,建立有向图,然后用Dijkstra跑最短路.好题! /************************************************ * Author :Running_Time * Created Time :2015/10/24 星期六 09:48:49 * File Name :POJ_1556.cpp…

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{…

  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…

题目: 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 = 10. The initial and final points of the path are always (0, 5) and (10…