T - Posterized(贪心思维)
Description
Professor Ibrahim has prepared the final homework for his algorithm’s class. He asked his students to implement the Posterization Image Filter.
Their algorithm will be tested on an array of integers, where the i-th integer represents the color of the i-th pixel in the image. The image is in black and white, therefore the color of each pixel will be an integer between 0 and 255 (inclusive).
To implement the filter, students are required to divide the black and white color range [0, 255] into groups of consecutive colors, and select one color in each group to be the group’s key. In order to preserve image details, the size of a group must not be greater than k, and each color should belong to exactly one group.
Finally, the students will replace the color of each pixel in the array with that color’s assigned group key.
To better understand the effect, here is an image of a basking turtle where the Posterization Filter was applied with increasing k to the right.
To make the process of checking the final answer easier, Professor Ibrahim wants students to divide the groups and assign the keys in a way that produces the lexicographically smallest possible array.
Input
The first line of input contains two integers n and k (1≤n≤10^5, 1≤k≤256), the number of pixels in the image, and the maximum size of a group, respectively.
The second line contains n integers p1,p2,…,pn (0≤pi≤255), where pi is the color of the i-th pixel.
Output
Print n space-separated integers; the lexicographically smallest possible array that represents the image after applying the Posterization filter.
Examples
Input
4 3
2 14 3 4
Output
0 12 3 3
Input
5 2
0 2 1 255 254
Output
0 1 1 254 254
Note
One possible way to group colors and assign keys for the first sample:
Color 2 belongs to the group [0,2], with group key 0.
Color 14 belongs to the group [12,14], with group key 12.
Colors 3 and 4 belong to group [3,5], with group key 3.
Other groups won't affect the result so they are not listed here.
解题思路:题目的意思就是以每一个像素的大小x为区间右端点,从[x-k+1,x]这个区间中尽可能选择一个比较小的值,作为这个区间的key值;用vis数组来判断这个区间(初始值都为-1)是否已经占用,如果已被占用即vis[x]!=-1,则不用处理;如果没有占用,遍历这个区间找最小可能代替的值,最大为x,然后依次用这个最小值t来覆盖区间[x-k+1,x]中还没有被覆盖的元素,最后输出每个数对应区间的最小key值即可。贪心思维填充区间key值~
AC代码:
#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+;
int n,k,vis[],a[maxn];
int main(){
memset(vis,-,sizeof(vis));//先初始化为-1,表示该区间还未使用
cin>>n>>k;
for(int i=;i<n;++i){
cin>>a[i];
if(vis[a[i]]==-){//判断是否已处于区间中,这里表示未被使用
int t=a[i]-k+;//如果不在区间中,那么最小值可能为t,最大值不超过本身a[i]
if(t<)t=;//如果t小于0,那么t最小为0
while(vis[t]!=-&&vis[t]!=t)t++;//如果这个数已经处于其他区间了,那么t++,找出该区间可以使用的最小值,最大等于t本身
for(int j=t;j<=a[i];++j)vis[j]=t;//将其他点覆盖为t,同样最大到本身,划分区间完毕
}
}
for(int i=;i<n;++i)//输出每个数对应的区间
cout<<vis[a[i]]<<(i==n-?'\n':' ');
return ;
}
T - Posterized(贪心思维)的更多相关文章
- Mike and distribution CodeForces - 798D (贪心+思维)
题目链接 TAG: 这是我近期做过最棒的一道贪心思维题,不容易想到,想到就出乎意料. 题意:给定两个含有N个正整数的数组a和b,让你输出一个数字k ,要求k不大于n/2+1,并且输出k个整数,范围为1 ...
- Codeforces Round #546 (Div. 2) D 贪心 + 思维
https://codeforces.com/contest/1136/problem/D 贪心 + 思维 题意 你面前有一个队列,加上你有n个人(n<=3e5),有m(m<=个交换法则, ...
- 贪心/思维题 Codeforces Round #310 (Div. 2) C. Case of Matryoshkas
题目传送门 /* 题意:套娃娃,可以套一个单独的娃娃,或者把最后面的娃娃取出,最后使得0-1-2-...-(n-1),问最少要几步 贪心/思维题:娃娃的状态:取出+套上(2),套上(1), 已套上(0 ...
- 贪心/思维题 UVA 11292 The Dragon of Loowater
题目传送门 /* 题意:n个头,m个士兵,问能否砍掉n个头 贪心/思维题:两个数组升序排序,用最弱的士兵砍掉当前的头 */ #include <cstdio> #include <c ...
- CF980C Posterized 贪心 二十五
Posterized time limit per test 1 second memory limit per test 256 megabytes input standard input out ...
- C. Coffee Break 贪心 思维 有点难 有意思
C. Coffee Break 这个贪心之前好像写过,还是感觉挺难的,有点不会写. 这个题目大意是:给你一个数列n个元素,然后给你一天的时间,给你一个间隔时间d, 问你最少要用多少天可以把这个数列的所 ...
- hdu 4803 贪心/思维题
http://acm.hdu.edu.cn/showproblem.php?pid=4803 话说C++还卡精度么? G++ AC C++ WA 我自己的贪心策略错了 -- 就是尽量下键,然后上 ...
- ZOJ 3829 贪心 思维题
http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3829 现场做这道题的时候,感觉是思维题.自己智商不够.不敢搞,想着队友智商 ...
- C. Brutality Educational Codeforces Round 59 (Rated for Div. 2) 贪心+思维
C. Brutality time limit per test 1 second memory limit per test 256 megabytes input standard input o ...
随机推荐
- hdu - 2066 一个人的旅行(基础最短路)
http://acm.hdu.edu.cn/showproblem.php?pid=2066 把与草儿相连的城市最短距离置为0,然后进行dijkstra,在t个城市里找出距离最近的一个即可. #inc ...
- WebLogic11g-创建域(Domain)及基本配置
最近看到经常有人提问weblogic相关问题,所以闲暇之际写几篇博文(基于weblogic11),仅供大家参考. 具体weblogic的介绍以及安装,这里就不赘述了. 以域的创建开篇,虽然简单,但 ...
- [大雾雾雾雾] 告别该死的 EFCore Fluent API
[EF Core Oracle 列名大小写问题] [EF Core Oracle column name case problem] [EF Core PostgreSql 列名大小写问题] [EF ...
- 淘宝后台添加颜色尺码动态sku
废话不多说,直接上代码,用了vue,可直接copy运行 <!DOCTYPE html> <html lang="en"> <head> < ...
- 条款五:对应的new和delete要采用相同的形式
string *stringarray = new string[100]; ... delete stringarray; 上述程序的运行情况将是不可预测的.至少,stringarray指向的100 ...
- POJ 1384 POJ 1384 Piggy-Bank(全然背包)
链接:http://poj.org/problem?id=1384 Piggy-Bank Time Limit: 1000MS Memory Limit: 10000K Total Submissio ...
- [Debug] Node-sass
Meet some problem when trying to install node-sass on windwos. Company has proxy settings, need to r ...
- Sharpdevelop如何在项目中添加类文件
点击文件-新建-文件,然后再工程内创建文件 或者工程-添加-新建项
- Linux下完美使用find+grep实现全局代码搜索
作者:zhanhailiang 日期:2014-10-11 背景 在Window下有大量方便的图形化工具能够实现全局搜索,可是Linuxserver中因为使用命令行操作导致全局搜索是一个比較高的门槛. ...
- IOS-Storyboard控制器切换之Modal(1)
Modal模式是指模态切换.新开的界面会挡住之前的界面,使之不能获取焦点. 创建一个singleView模板的程序,打开storyboard文件.拖动2个UIViewController到界面中.按住 ...