// 叉积判断 POJ1696 #include <iostream> #include <algorithm> #include <cstring> #include <cstdio> #include <vector> #include <cmath> #include <map> using namespace std; #define LL long long typedef pair<int,int>…

题目大意:给你一个矩形的左上角和右下角的坐标,然后这个矩形有 N 个隔板分割成 N+1 个区域,下面有 M 组坐标,求出来每个区域包含的坐标数.   分析:做的第一道计算几何题目....使用叉积判断方向,然后使用二分查询找到点所在的区域.   代码如下: ==========================================================================================================================…

TOYS Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 13120   Accepted: 6334 Description Calculate the number of toys that land in each bin of a partitioned toy box. Mom and dad have a problem - their child John never puts his toys away w…

题目链接 Toy Storage Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 4104   Accepted: 2433 Description Mom and dad have a problem: their child, Reza, never puts his toys away when he is finished playing with them. They gave Reza a rectangula…

题目链接:https://vjudge.net/problem/POJ-1556 题意:在一个矩形内,起点(0,5)和终点(10,5)是固定的,中间有n个道墙(n<=18),每道墙有两个門,求起点到终点的最短路. 思路: 最多有4*n+2个点,枚举所有点对(p1,p2),用叉积判断线段p1p2和中间的墙是否相交,不相交那么更新距离为两点的距离,否则为inf.更新所有的边之后用floyd得到最短路.答案即dist[0][4*n+1].时间复杂度O(n^3). AC code: #include<…

题目链接 题意:一个矩形被分成了n + 1块,然后给出m个点,求每个点会落在哪一块中,输出每块的点的个数 就是判断 点与直线的位置,点在直线的逆时针方向叉积 < 0,点在直线的顺时针方向叉积 > 0 // 可以选择二分查找 #include <iostream> #include <algorithm> #include <cstdio> #include <cstring> using namespace std; typedef long l…

TOYS Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 8661   Accepted: 4114 Description Calculate the number of toys that land in each bin of a partitioned toy box. Mom and dad have a problem - their child John never puts his toys away wh…

题目:http://poj.org/problem?id=2318 题意: 给定一个如上的长方形箱子,中间有n条线段,将其分为n+1个区域,给定m个玩具的坐标,统计每个区域中的玩具个数.(其中这些线段有序且不相交) 解答: 因为线段是有序给出,所以不用排序,判断某个点在哪个区域,采用二分法,将某个点和线段的叉积来判断这个点是在线的左边或者右边,根据这个来二分找出区域. 这是第一道计算几何的题目,怎么说呢,对于二分的边界问题还有点搞不清楚,这次是对线段二分,感觉二分真的很有用处. 开阔思维!!!具…

Toy Storage Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6534   Accepted: 3905 Description Mom and dad have a problem: their child, Reza, never puts his toys away when he is finished playing with them. They gave Reza a rectangular box…

TOYS Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 17974   Accepted: 8539 Description Calculate the number of toys that land in each bin of a partitioned toy box. Mom and dad have a problem - their child John never puts his toys away w…