codeforces 949B A Leapfrog in the Array
2 seconds
512 megabytes
standard input
standard output
Dima is a beginner programmer. During his working process, he regularly has to repeat the following operation again and again: to remove every second element from the array. One day he has been bored with easy solutions of this problem, and he has come up with the following extravagant algorithm.
Let's consider that initially array contains n numbers from 1 to n and the number i is located in the cell with the index 2i - 1 (Indices are numbered starting from one) and other cells of the array are empty. Each step Dima selects a non-empty array cell with the maximum index and moves the number written in it to the nearest empty cell to the left of the selected one. The process continues until all n numbers will appear in the first n cells of the array. For example if n = 4, the array is changing as follows:

You have to write a program that allows you to determine what number will be in the cell with index x(1 ≤ x ≤ n) after Dima's algorithm finishes.
The first line contains two integers n and q (1 ≤ n ≤ 1018, 1 ≤ q ≤ 200 000), the number of elements in the array and the number of queries for which it is needed to find the answer.
Next q lines contain integers xi (1 ≤ xi ≤ n), the indices of cells for which it is necessary to output their content after Dima's algorithm finishes.
For each of q queries output one integer number, the value that will appear in the corresponding array cell after Dima's algorithm finishes.
4 3
2
3
4
3
2
4
13 4
10
5
4
8
13
3
8
9
The first example is shown in the picture.
In the second example the final array is [1, 12, 2, 8, 3, 11, 4, 9, 5, 13, 6, 10, 7].
题意:题中四张图已经说明题意
数组中隔一个放个数字,然后找最后一个往最近的空子里塞
q个询问,求最后在某个位置上的数字是什么。
题解:把过程倒过来考虑:
从最终状态开始,按照规则把被塞进的数移动回数组最后。
就是按照4,3,2,1的顺序看题目中的图,递归模拟,注意细节。
/*
Welcome Hacking
Wish You High Rating
*/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<ctime>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<string>
using namespace std;
int read(){
int xx=,ff=;char ch=getchar();
while(ch>''||ch<''){if(ch=='-')ff=-;ch=getchar();}
while(ch>=''&&ch<=''){xx=(xx<<)+(xx<<)+ch-'';ch=getchar();}
return xx*ff;
}
long long READ(){
long long xx=,ff=;char ch=getchar();
while(ch>''||ch<''){if(ch=='-')ff=-;ch=getchar();}
while(ch>=''&&ch<=''){xx=(xx<<)+(xx<<)+ch-'';ch=getchar();}
return xx*ff;
}
long long N,q;
int Q;
inline long long can(long long a,long long b){//计算在连续区间内有几个元素是需要移动的(下标为偶数)
long long seq=(b-a+);
if(seq<=)
return ;
if(seq&){
if(b&)
return seq/;
else
return seq/+;
}
else
return seq/;
}
void dfs(long long now,long long L,long long R){//now:询问元素所在的位置 L:可能移动的连续区间左端点 R:右端点
long long t=R+can(L,R);
if(R<now)
dfs(now,R+,t);
else{
long long np=can(L,now-)+R+;//np:now移动后应该在的位置
if(np>N||(now&)){
printf("%I64d\n",now/+);
return;
}
dfs(np,now+,np);
}
}
int main(){
//freopen("in","r",stdin);
N=READ()*-,Q=read();
for(int i=;i<=Q;i++){
q=READ();
long long r=N/+;
dfs(q,,r);
}
return ;
}
codeforces 949B A Leapfrog in the Array的更多相关文章
- codeforces 949B :A Leapfrog in the Array 找规律
题意: 现在给你一个n,表示有2*n-1个方格,第奇数方格上会有一个数字 1-n按顺序放.第偶数个方格上是没有数字的.变动规则是排在最后一个位置的数字,移动到它前边最近的空位 . 直到数字之间没有空位 ...
- Codeforces 950D A Leapfrog in the Array (思维)
题目链接:A Leapfrog in the Array 题意:给出1-n的n个数,从小到大每隔一个位置放一个数.现在从大到小把数往前移动,每次把最右边的数移动最靠右边的空格处直到n个数都在前n个位置 ...
- CodeForces - 950D A Leapfrog in the Array 玄学题
题意:n个数1~n(n<=1e18)依次放在一个数组中,第i个数位置为2i-1,其它地方是空的.现在重复以下操作:将最右边的数放到离其左边最近的空的位置,直到所有数移到前一半的位置中.有q< ...
- Codeforces 950D A Leapfrog in the Array ( 思维 && 模拟 )
题意 : 给出 N 表示有标号 1~N 的 N 个数,然后从下标 1 开始将这 N 个数每隔一位放置一个,直到 N 个数被安排完,现在有一个操作就是每次将数列中最右边的数向离其左边最近的空缺处填上,一 ...
- Codeforces 221d D. Little Elephant and Array
二次联通门 : Codeforces 221d D. Little Elephant and Array /* Codeforces 221d D. Little Elephant and Array ...
- Codeforces 950 D. A Leapfrog in the Array
http://codeforces.com/contest/950/problem/D 前n/2个格子的奇数下标的数没有参与移动 候n/2个格子的奇数下标的数一定是一路移向偶数下标移 所以还原数的初始 ...
- Codeforces Round #181 (Div. 2) A. Array 构造
A. Array 题目连接: http://www.codeforces.com/contest/300/problem/A Description Vitaly has an array of n ...
- B. A Leapfrog in the Array
http://codeforces.com/problemset/problem/949/B Dima is a beginner programmer. During his working pro ...
- Codeforces Round #284 (Div. 1) C. Array and Operations 二分图最大匹配
题目链接: http://codeforces.com/problemset/problem/498/C C. Array and Operations time limit per test1 se ...
随机推荐
- ThinkPHP---AR模式
[前言] 在之前学习框架时介绍过 (1)什么是框架? ①框架是一堆包含了常量.方法和类等代码集合: ②半成品应用,只包含了项目开发时的底层架构,并不包含业务逻辑: ③包含一些设计模式,例如单例模式,工 ...
- pl/sql编程语言
–pl/sql编程语言–pl/sql编程语言是对sql语言的扩展,是的sql语言具有过程化编程的特性–pl/sql编程语言比一般的过程化编程语言,更加灵活高效–pl/sql编程语言主要用来编写存储过程 ...
- 荷兰国旗问题、快排以及BFPRT算法
荷兰国旗问题 给定一个数组arr,和一个数num,请把小于num的数放数组的左边,等于num的数放在数组的中间,大于num的数放在数组的右边.要求额外空间复杂度O(1),时间复杂度O(N). 这个问题 ...
- Cyclic Nacklace HDU - 3746 (kmp next数组应用)
题目大意 给出字符串,寻找最小要补全的字符个数,使得字符串是两次的循环 解法 通过寻找规律,我们又发现了len-next[len]又派上了用场 ①如果next[len]是0,说明最大前缀后缀和为0,那 ...
- 手机端--tap PC端--click
区别: tap为jq mobile 的方法 1.click与tap都会触发点击事件,但是在手机web端,click会有200-300ms的延迟,所以一般用tap代替click作为点击事件.single ...
- db2构建临时结果集
一 values ('1',2,3) 为一行 ‘1’ 2 3 行数据类型可以不同 values ('1',2,3),('f',5,6) 为两行 (values 1,2,3 ...
- PHP 锁机制
应用环境 解决高并发,库存为负数的情况 阻塞模式 如果其他进程已经加锁文件,当前进程会一直等其他进程解锁文件后继续执行 flock($fp, LOCK_EX) // 文件锁 非阻塞模式 如果其他进程已 ...
- 根据屏幕的大小改变rem的参考值
移动端一半会选用rem+flex布局的方式,下面是根据屏幕的宽度,动态的改变rem的参考值 var screenWidth; var html = document.getEl ...
- 51NOD欧姆诺姆和项链——KMP算法(非水题)
>>点击进入原题测试<< 思路:好久不见,今天要开始真正写题了.这个题之前我的理解有点问题,导致写了很久最终都是一直都只能过样例.需要注意的是输出中每一个“1”都是和别的输出相 ...
- 洛谷—— P1825 [USACO11OPEN]玉米田迷宫Corn Maze
https://www.luogu.org/problem/show?pid=1825 题目描述 This past fall, Farmer John took the cows to visit ...