Codeforces 715A. Plus and Square Root[数学构造]
2 seconds
256 megabytes
standard input
standard output
ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) and '
' (square root). Initially, the number 2 is displayed on the screen. There are n + 1 levels in the game and ZS the Coder start at the level 1.
When ZS the Coder is at level k, he can :
- Press the ' + ' button. This increases the number on the screen by exactly k. So, if the number on the screen was x, it becomes x + k.
- Press the '
' button. Let the number on the screen be x. After pressing this button, the number becomes
. After that, ZS the Coder levels up, so his current level becomes k + 1. This button can only be pressed when x is a perfect square, i.e. x = m2 for some positive integer m.
Additionally, after each move, if ZS the Coder is at level k, and the number on the screen is m, then m must be a multiple of k. Note that this condition is only checked after performing the press. For example, if ZS the Coder is at level 4 and current number is 100, he presses the '
' button and the number turns into 10. Note that at this moment, 10 is not divisible by 4, but this press is still valid, because after it, ZS the Coder is at level 5, and 10 is divisible by 5.
ZS the Coder needs your help in beating the game — he wants to reach level n + 1. In other words, he needs to press the '
' button ntimes. Help him determine the number of times he should press the ' + ' button before pressing the '
' button at each level.
Please note that ZS the Coder wants to find just any sequence of presses allowing him to reach level n + 1, but not necessarily a sequence minimizing the number of presses.
The first and only line of the input contains a single integer n (1 ≤ n ≤ 100 000), denoting that ZS the Coder wants to reach level n + 1.
Print n non-negative integers, one per line. i-th of them should be equal to the number of times that ZS the Coder needs to press the ' + ' button before pressing the '
' button at level i.
Each number in the output should not exceed 1018. However, the number on the screen can be greater than 1018.
It is guaranteed that at least one solution exists. If there are multiple solutions, print any of them.
3
14
16
46
2
999999999999999998
44500000000
4
2
17
46
97
In the first sample case:
On the first level, ZS the Coder pressed the ' + ' button 14 times (and the number on screen is initially 2), so the number became 2 + 14·1 = 16. Then, ZS the Coder pressed the '
' button, and the number became
.
After that, on the second level, ZS pressed the ' + ' button 16 times, so the number becomes 4 + 16·2 = 36. Then, ZS pressed the '
' button, levelling up and changing the number into
.
After that, on the third level, ZS pressed the ' + ' button 46 times, so the number becomes 6 + 46·3 = 144. Then, ZS pressed the '
' button, levelling up and changing the number into
.
Note that 12 is indeed divisible by 4, so ZS the Coder can reach level 4.
Also, note that pressing the ' + ' button 10 times on the third level before levelling up does not work, because the number becomes 6 + 10·3 = 36, and when the '
' button is pressed, the number becomes
and ZS the Coder is at Level 4. However, 6 is not divisible by 4 now, so this is not a valid solution.
In the second sample case:
On the first level, ZS the Coder pressed the ' + ' button 999999999999999998 times (and the number on screen is initially 2), so the number became 2 + 999999999999999998·1 = 1018. Then, ZS the Coder pressed the '
' button, and the number became
.
After that, on the second level, ZS pressed the ' + ' button 44500000000 times, so the number becomes 109 + 44500000000·2 = 9·1010. Then, ZS pressed the '
' button, levelling up and changing the number into
.
Note that 300000 is a multiple of 3, so ZS the Coder can reach level 3.
题意:当前数字a[k](a[k]是k的倍数)要么+k,要么开根得到a[i+1](必须完全平方根),问每次得到下一个数要几次加
想了个暴力,枚举c当前数是c*c*(k+1)*(k+1),找满足a[k]+k*d的
然而正解是构造,好神奇
------------------------------------
官方题解:
Firstly, let ai(1 ≤ i ≤ n) be the number on the screen before we level up from level i to i + 1. Thus, we require all the ais to be perfect square and additionally to reach the next ai via pressing the plus button, we require
and
for all 1 ≤ i < n. Additionally, we also require ai to be a multiple of i. Thus, we just need to construct a sequence of such integers so that the output numbers does not exceed the limit 1018.
There are many ways to do this. The third sample actually gave a large hint on my approach. If you were to find the values of ai from the second sample, you'll realize that it is equal to 4, 36, 144, 400. You can try to find the pattern from here. My approach is to use ai = [i(i + 1)]2. Clearly, it is a perfect square for all 1 ≤ i ≤ n and when n = 100000, the output values can be checked to be less than 1018
Unable to parse markup [type=CF_TEX]
which is a multiple of i + 1, and
is also a multiple of i + 1.
------------------------------
a[i]=i*i*(i+1)*(i+1)
因为a[i]是i的倍数又是(i+1)平方的倍数并且a[i]<a[i+1]
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<ctime>
using namespace std;
typedef long long ll;
int n,k=;
ll x=;
int main(int argc, const char * argv[]) {
scanf("%d",&n);
printf("2\n");
for(int k=;k<=n;k++){
printf("%I64d\n",(ll)k*(k+)*(k+)-(k-));
} return ;
}
Codeforces 715A. Plus and Square Root[数学构造]的更多相关文章
- codeforces 509 D. Restoring Numbers(数学+构造)
题目链接:http://codeforces.com/problemset/problem/509/D 题意:题目给出公式w[i][j]= (a[i] + b[j])% k; 给出w,要求是否存在这样 ...
- Codeforces 715A & 716C Plus and Square Root【数学规律】 (Codeforces Round #372 (Div. 2))
C. Plus and Square Root time limit per test 2 seconds memory limit per test 256 megabytes input stan ...
- Codeforces Round #372 (Div. 1) A. Plus and Square Root 数学题
A. Plus and Square Root 题目连接: http://codeforces.com/contest/715/problem/A Description ZS the Coder i ...
- Codeforces 612E - Square Root of Permutation
E. Square Root of Permutation A permutation of length n is an array containing each integer from 1 t ...
- 【CodeForces】708 B. Recover the String 数学构造
[题目]B. Recover the String [题意]找到一个串s,满足其中子序列{0,0}{0,1}{1,0}{1,1}的数量分别满足给定的数a1~a4,或判断不存在.数字<=10^9, ...
- Codeforces 716C. Plus and Square Root-推公式的数学题
http://codeforces.com/problemset/problem/716/C codeforces716C. Plus and Square Root 这个题就是推,会推出来规律,发现 ...
- Project Euler 80:Square root digital expansion 平方根数字展开
Square root digital expansion It is well known that if the square root of a natural number is not an ...
- (Problem 57)Square root convergents
It is possible to show that the square root of two can be expressed as an infinite continued fractio ...
- Square Root
Square RootWhen the square root functional configuration is selected, a simplified CORDIC algorithm ...
随机推荐
- AngularJS结合RequireJS做文件合并压缩的那些坑
我在项目使用了AngularJS框架,用RequireJS做异步模块加载(AMD),在做文件合并压缩时,遇到了一些坑,有些只是解决了,但不明白原因. 那些坑 1. build.js里面的paths必须 ...
- python之socket开发
socket通常也称作"套接字",用于描述IP地址和端口,是一个通信链的句柄,应用程序通常通过"套接字"向网络发出请求或者应答网络请求. socket起源于Un ...
- Sharepoint学习笔记—习题系列--70-576习题解析 -(Q56-Q58)
Question 56You work for a manufacturer who needs to advertise its catalog of products online using a ...
- C语言一级指针与二级指针
指针的概念 指针就是地址, 利用这个地址可以找到指定的数据 指针就是地址, 那么在使用的时候, 常常会简单的说 指针变量为指针 指针变量就是存储地址的变量 int *p1;// 申请了一个变量, 即在 ...
- WCF服务配置编辑器使用
学习wcf,特别是初学者,配置文件很难搞懂,有点复杂,自己手动配置哪有这么多精力啊,这不是吃的太饱了吗,所以学会使用配置编辑器是必须的,下面是学习的流程图. 打开工具的wcf服务配置编辑器,点击文件= ...
- [Android]AndroidBucket增加碎片SubLayout功能及AISubLayout的注解支持
以下内容为原创,转载请注明: 来自天天博客:http://www.cnblogs.com/tiantianbyconan/p/3709957.html 之前写过一篇博客,是使用Fragment来实现T ...
- Android 触摸手势基础 官方文档概览
Android 触摸手势基础 官方文档概览 触摸手势检测基础 手势检测一般包含两个阶段: 1.获取touch事件数据 2.解析这些数据,看它们是否满足你的应用所支持的某种手势. 相关API: Moti ...
- Ubuntu Server 14.04升级Ubuntu Server 16.04
Ubuntu Server 14.04升级Ubuntu Server 16.04 :转 http://blog.csdn.net/chszs 1.终端下执行命令 $ sudo apt-get upda ...
- 【读书笔记】iOS网络-使用Bonjour实现自组织网络
Bonjour就是这样一种技术:设备可以通过它轻松探测并连接到相同网络中的其他设备,整个过程只需要很少的用户参与或是根本就不需要用户参与.该框架提供了众多适合于移动的使用场景,如基于网络的游戏,设备间 ...
- UISegmentedControl(人物简介)
效果图 当你点击上面人物名字的时候 ,就可以随意切换人物. 这个很有趣 , 你还可以试着添加音乐播放器 .以及一些别的来完善你想做的. 好吧 , 废话不多说 , 上代码. #import " ...