poj 2318 向量的叉积二分查找】的更多相关文章

TOYS Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 9350   Accepted: 4451 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…
题目传送门:POJ 2318 TOYS 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 when he is finished playing with them. They gave John a rectangular bo…
今天开始学习计算几何,百度了两篇文章,与君共勉! 计算几何入门题推荐 计算几何基础知识 题意:有一个盒子,被n块木板分成n+1个区域,每个木板从左到右出现,并且不交叉. 有m个玩具(可以看成点)放在这个盒子里,问每个区域分别有多少个玩具. 思路:首先,用叉积判断玩具是否在木板的左边,再用二分找到符合的最右边的木板,该木板答案加一. #include<stdio.h> #include<string.h> struct point{ int x,y; point(){} point(…
POJ 1064 Cable master 一开始把 int C(double x) 里面写成了  int C(int x) ,莫名奇妙竟然过了样例,交了以后直接就wa. 后来发现又把二分查找的判断条件写错了,wa了n次,当 c(mid)<=k时,令ub=mid,这个判断是错的,因为要找到最大切割长度,当满足这个条件时,可能已经不是最大长度了,此时还继续缩小区间,自然就wa了,(从大到小递减,第一次满足这个条件的值,就是最大的值),正确的判断是当 c(mid)<k时,令ub=mid,这样循环1…
题意:给定n(<=5000)条线段,把一个矩阵分成了n+1分了,有m个玩具,放在为位置是(x,y).现在要问第几个位置上有多少个玩具. 思路:叉积,线段p1p2,记玩具为p0,那么如果(p1p2 ^ p1p0) (记得不能搞反顺序,不同的),如果他们的叉积是小于0,那么就是在线段的左边,否则右边.所以,可以用二分找,如果在mid的左边,end=mid-1 否则begin=mid+1.结束的begin,就是第一条在点右边的线段 #include <cstdio> #include <…
Number Sequence Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 36013   Accepted: 10409 Description A single positive integer i is given. Write a program to find the digit located in the position i in the sequence of number groups S1S2..…
用叉积判断左右 快速读入写错了卡了3小时hhh #include<cmath> #include<cstdio> #include<cstring> #include<algorithm> #define N 5003 #define read(x) x = getint() using namespace std; inline int getint() { int fh = 1, k = 0; char c = getchar(); for(; c &l…
Aggressive cows Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5436   Accepted: 2720 Description Farmer John has built a new long barn, with N (2 <= N <= 100,000) stalls. The stalls are located along a straight line at positions x1,...…
Cable master Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 21071   Accepted: 4542 Description Inhabitants of the Wonderland have decided to hold a regional programming contest. The Judging Committee has volunteered and has promised to…
一个不错的二分,注释在代码里 #include <stdio.h> #include <cstring> #include <algorithm> #include <cmath> #include <iostream> using namespace std; ///二分搜索答案,最大化最小值 int main() { int L,n,m; ]; while(~scanf("%d %d %d",&L,&n,&…