解题关键: n的环排列的个数与n-1个元素的排列的个数相等. 首先可以肯定,无论从最左边还是从最右边看,最高的那个楼一定是可以看到的,从这里入手. 假设最高的楼的位置固定,最高楼的编号为n,那么我们为了满足条件,可以在楼n的左边分x-1组,右边分y-1组,且用每组最高的那个元素代表这一组,那么楼n的左边,从左到右,组与组之间最高的元素一定是单调递增的,且每组中的最高元素一定排在该组的最左边,每组中的其它元素可以任意排列(相当于这个组中所有元素的环排列).右边反之亦然. 最高的那个楼左边一定有x-…

[Hdu4372] Count the Buildings Description There are N buildings standing in a straight line in the City, numbered from 1 to N. The heights of all the buildings are distinct and between 1 and N. You can see F buildings when you standing in front of th…

题目链接:https://vjudge.net/problem/HDU-4372 Count the Buildings Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 2509    Accepted Submission(s): 815 Problem Description There are N buildings standin…

@(HDU)[Stirling數, 排列組合] Problem Description There are N buildings standing in a straight line in the City, numbered from 1 to N. The heights of all the buildings are distinct and between 1 and N. You can see F buildings when you standing in front of…

题面 (笔者翻译) There are N buildings standing in a straight line in the City, numbered from 1 to N. The heights of all the buildings are distinct and between 1 and N. 有n座高楼,从左往右数第 i 座楼的高度为 ai,每座高楼高度互不相同,且 1 ≤ ai ≤ n ,换言之,n座高楼高度形成的序列为1~n的一个排列. You can see…

2017-08-10 21:10:08 writer:pprp //TLE #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> #include <algorithm> using namespace std; const int INF = 0x3f3f3f3f; typedef long long…

Description $N$座高楼,高度均不同且为$1~N$中的数,从前向后看能看到$F$个,从后向前看能看到$B$个,问有多少种可能的排列数. $T$组询问,答案模$1000000007$.其中$n\leq 2000,T\leq 100000$ 题解: 可以考虑现将最高的拿出来,那么可以考虑左边需要有$F-1$个房子成递增关系,那么可以将左边的房子分成$F-1$个组,右边有$B-1$个房子成递减关系,也是如此. 不禁想到第一类斯特林数,$s(p,k)$是将将$p$个物体排成$k$个非空循环排…

http://acm.hdu.edu.cn/game/entry/problem/list.php?chapterid=1§ionid=2 1.2.5 #include<stdio.h> /* 题意:找闰年. if((i%4==0 && i%100!=0) || i%400==0)count++; 3 2005 25 1855 12 2004 10000 2108 1904 43236 */ int main() { int t,y,n; int i,count=0; whil…

在上篇,我了解了基数的基本概念,现在进入Linear Counting算法的学习. 理解颇浅,还请大神指点! http://blog.codinglabs.org/articles/algorithms-for-cardinality-estimation-part-ii.html 它的基本处理方法和上篇中用bitmap统计的方法类似,但是最后要用到一个公式: 说明:m为bitmap总位数,u为0的个数,最后的结果为n的一个估计,且为最大似然估计(MLE). 那么问题来了,最大似然估计是什么东东…

来之不易的2017第一发ac http://poj.org/problem?id=2386 Lake Counting Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 31474   Accepted: 15724 Description Due to recent rains, water has pooled in various places in Farmer John's field, which is repr…

You want to build a house on an empty land which reaches all buildings in the shortest amount of distance. You can only move up, down, left and right. You are given a 2D grid of values 0, 1 or 2, where: Each 0 marks an empty land which you can pass b…

ZOJ3944 People Counting ZOJ3939 The Lucky Week 1.PeopleConting 题意:照片上有很多个人,用矩阵里的字符表示.一个人如下: .O. /|\ (.) 占3*3格子,句号“.”为背景.没有两个人完全重合.有的人被挡住了一部分.问照片上有几个人. 题解: 先弄个常量把3*3人形存起来,然后6个部位依次找,比如现在找头,找到一个头,就把这个人删掉(找这个人的各个部位,如果在该部位位置的不是这个人的身体,就不删),删成句号,疯狂找就行了. 代码:…

#include <stdio.h> #include <malloc.h> #define MAX_STACK 10 ; // define the node of stack typedef struct node { int data; node *next; }*Snode; // define the stack typedef struct Stack{ Snode top; Snode bottom; }*NewStack; void creatStack(NewSt…

1004. Counting Leaves (30)   A family hierarchy is usually presented by a pedigree tree. Your job is to count those family members who have no child. Input Each input file contains one test case. Each case starts with a line containing 0 < N < 100,…

Problem Figure 2. The Hamming distance between these two strings is 7. Mismatched symbols are colored red. Given two strings ss and tt of equal length, the Hamming distance between ss and tt, denoted dH(s,t)dH(s,t), is the number of corresponding sym…

Problem A string is simply an ordered collection of symbols selected from some alphabet and formed into a word; the length of a string is the number of symbols that it contains. An example of a length 21 DNA string (whose alphabet contains the symbol…

// uva 11401 Triangle Counting // // 题目大意: // // 求n范围内,任意选三个不同的数,能组成三角形的个数 // // 解题方法: // // 我们设三角巷的最长的长度是c(x),另外两边为y,z // 则由z + y > x得, x - y < z < x 当y = 1时,无解 // 当y = 2时,一个解,这样到y = x - 1 时 有 x - 2个 // 解,所以一共是0,1,2,3....x - 2,一共(x - 2) * (x - 1…

当我们在使用JSONKit处理数据时,直接将文件拉进项目往往会报这两个错“JSONKit   does not support Objective-C Automatic Reference Counting(ARC)”,“ARC forbids Objective-C objects in struct”,这是由于JSONKit库未更新,不支持ARC机制.我们可以参照如下步骤解决:…

有使用JSonKit的朋友,如果遇到“JSonKit does not support Objective-C Automatic Reference Counting(ARC)”这种情况,可参照如下方法: 点击项目根目录->targets->Build Phases->JSONKit.m->添加“-fno-objc-arc”字段,在运行就OK了.…

Lake Counting Time Limit: 1000MS     Memory Limit: 65536K Total Submissions: 17917     Accepted: 9069 Description Due to recent rains, water has pooled in various places in Farmer John's field, which is represented by a rectangle of N x M (1 <= N <=…

Boring Counting Time Limit: 3000ms   Memory limit: 65536K  有疑问?点这里^_^ 题目描述     In this problem you are given a number sequence P consisting of N integer and Pi is the ith element in the sequence. Now you task is to answer a list of queries, for each…

Boring counting Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 98304/98304 K (Java/Others) Total Submission(s): 2811    Accepted Submission(s): 827 Problem Description In this problem we consider a rooted tree with N vertices. The vertices a…

Counting Squares Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 1885    Accepted Submission(s): 946 Problem Description Your input is a series of rectangles, one per line. Each rectangle is sp…

原题链接在这里:https://leetcode.com/problems/shortest-distance-from-all-buildings/ 题目: You want to build a house on an empty land which reaches all buildings in the shortest amount of distance. You can only move up, down, left and right. You are given a 2D…

http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2610 Boring Counting Time Limit: 3000ms   Memory limit: 65536K  有疑问?点这里^_^ 题目描述     In this problem you are given a number sequence P consisting of N integer and Pi is the ith ele…

转载地址:http://blog.csdn.net/xbl1986/article/details/7216668 Xcode是Version 4.2 Build 4D151a 根据Objective-c 2.0程序设计上的旧版本的代码会发生NSAutoreleasePool' is unavailable: not available in automatic reference counting mode的错误 需要手动关闭工程中ARC 工程中 Build Settings--->Apple…

Boring counting Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 98304/98304 K (Java/Others) Problem Description In this problem we consider a rooted tree with N vertices. The vertices are numbered from 1 to N, and vertex 1 represents the root…

Counting Offspring Time Limit: 15000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description You are given a tree, it’s root is p, and the node is numbered from 1 to n. Now define f(i) as the number of nodes whose numbe…

题目描述 "But baby, I've been, I've been praying hard,     Said, no more counting dollars     We'll be counting stars" Grandpa Shaw loves counting stars. One evening he was sitting in his armchar, trying to figure out this problem. Consider the sky…

Counting Bits Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and return them as an array. Example:For num = 5 you should return [0,1,1,2,1,2]. Follow up…