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
- spring web MVC
详情:http://blog.csdn.net/mic_hero/article/details/50237627
- php强制转换类型和CMS远程管理插件的危险
远程管理插件是十分受WordPress站点管理员欢迎的工具,它们允许用户同时对多个站点执行相同的操作,如,更新到最新的发行版或安装插件.然而,为了实现这些操作,客户端插件需要赋予远程用户很大的权限.因 ...
- 2015年Java开发岗位面试题归类
一.Java基础 1. String类为什么是final的. 2. HashMap的源码,实现原理,底层结构. 3. 说说你知道的几个Java集合类:list.set.queue.map实现类咯... ...
- iOS开发-生成随机数
有时候我们需要在程序中生成随机数,但是在Objective-c中并没有提供相应的函数,好在C中提供了rand().srand().random().arc4random()几个函数.那么怎么使用呢?下 ...
- IOS NSTimer和CADisplayLink的用法
IOS--NSTimer和CADisplayLink的用法 NSTimer初始化器接受调用方法逻辑之间的间隔作为它的其中一个参数,预设一秒执行30次.CADisplayLink默认每秒运行60次,通过 ...
- 我曾经的第一个OC程序
一. OC简介 C语言的基础上,增加了一层最小的面向对象语法 完全兼容C语言 可以在OC代码中混入C语言代码,甚至是C++代码 可以使用OC开发Mac OS X平台和iOS平台的应用程序 二. OC语 ...
- EMLS项目推进思考
解决难度从小到大来看: 一.技术与运营层面1. 到企业级层面需要的技术与运营的支撑________前端推送__________________|________后台支撑系统_________|____ ...
- Asp.net MVC的Model Binder工作流程以及扩展方法(1) - Custom Model Binder
在Asp.net MVC中, Model Binder是生命周期中的一个非常重要的部分.搞清楚Model Binder的流程,能够帮助理解Model Binder的背后发生了什么.同时该系列文章会列举 ...
- JavaScript Patterns 5.6 Static Members
Public Static Members // constructor var Gadget = function (price) { this.price = price; }; // a sta ...
- zookeeper barrier和queue应用实例
package org.windwant.zookeeper; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper. ...