Skip to main content

Positive Prefixes Codechef December long challenge solution | Codechef December long challeng editorial

Problem Statement -

this Problem Positive prefix taken from CodeChef December long challenge.Let's read Problem statement.

You are given two positive integers N and K, where KN. Find a sequence A1,A2,,AN such that:

  • for each valid iAi is either i or i
  • there are exactly K values of i such that 1iN and A1+A2++Ai>0

If there are multiple solutions, you may print any one of them. It can be proved that at least one solution always exists.

Input

  • The first line of the input contains a single integer T denoting the number of test cases. The description of T test cases follows.
  • The first and only line of each test case contains two space-separated integers N and K.

Output

For each test case, print a single line containing N space-separated integers A1,A2,,AN.

Constraints

  • 1T1,000
  • 1KN1,000

Subtasks

Subtask #1 (10 points): N10

Subtask #2 (90 points): original constraints

Example Input

1
3 3

Example Output

1 2 3




Solution-

Hint- learn Prefix array to solve this question.
This question is totally observation-based.You should  good observer to solve  this problem.
Solution since there can be multiple solution of this problem one of them is to print alternate +i and -i.
in my case what i am doing 
I have created an output array in which i am storing +i and -i alternatively.
then I iterate over the array and I calculate the prefix array.
Then I calculated total positive and negative number store in the output array.And i build the following logic 
if(k<=positive){
            int diff=positive-k;
            for(int i=n;i>0&&diff>0;i--){
                if(prefix[i]>0){
                    output[i]=-output[i];
                    diff--;
                }
                

            }
        }
        else{
           int diff=k-positive;
             for(int i=n;i>0&&diff>0;i--){
                if(prefix[i]<0){
                    output[i]=-output[i];
                    diff--;
                }
                

            }
        }

Here is my entire code.

Join Telegram Channel for solution. 


Comments

Popular posts from this blog

codeforces rating system | Codeforces rating Newbie to Legendary Grandmaster

 Codeforces rating system | Codeforces rating Newbie to Legendary Grandmaster- Codeforces is one of the most popular platforms for competitive programmers and  codeforces rating matters a lot  .  Competitive Programming  teaches you to find the easiest solution in the quickest possible way. CP enhances your problem-solving and debugging skills giving you real-time fun. It's brain-sport. As you start solving harder and harder problems in live-contests your analytical and rational thinking intensifies. To have a good codeforces profile makes a good impression on the interviewer. If you have a good  codeforces profile so it is very easy to get a referral for product base company like amazon, google , facebook etc.So in this blog I have explained everything about codeforces rating system. What are different titles on codeforces- based on rating codeforces divide rating into 10 part. Newbie Pupil Specialist Expert Candidate Codemaster Master International Master Grandmaster Internat

Apple Division CSES Problem Set Solution | CSES Problem Set Solution Apple division with code

 Apple Division CSES Problem Set Solution | CSES Problem Set Solution Apple division with code - Apple Division CSES Problem Solution Easy Explanation. Apple division is problem is taken form cses introductory problem set.Let's Read Problem statement first. Problem Statement- Time limit:  1.00 s   Memory limit:  512 MB There are  n n  apples with known weights. Your task is to divide the apples into two groups so that the difference between the weights of the groups is minimal. Input The first input line has an integer  n n : the number of apples. The next line has  n n  integers  p 1 , p 2 , … , p n p 1 , p 2 , … , p n : the weight of each apple. Output Print one integer: the minimum difference between the weights of the groups. Constraints 1 ≤ n ≤ 20 1 ≤ n ≤ 20 1 ≤ p i ≤ 10 9 1 ≤ p i ≤ 10 9 Example Input: 5 3 2 7 4 1 Output: 1 Explanation: Group 1 has weights 2, 3 and 4 (total weight 9), and group 2 has weights 1 and 7 (total weight 8). Join Telegram channel for code discussi

Movie Festival CSES problem set solution

 Movie Festival CSES problem set solution - Problem statement-  Time limit:  1.00 s   Memory limit:  512 MB In a movie festival  n n  movies will be shown. You know the starting and ending time of each movie. What is the maximum number of movies you can watch entirely? Input The first input line has an integer  n n : the number of movies. After this, there are  n n  lines that describe the movies. Each line has two integers  a a  and  b b : the starting and ending times of a movie. Output Print one integer: the maximum number of movies. Constraints 1 ≤ n ≤ 2 ⋅ 10 5 1 ≤ n ≤ 2 ⋅ 10 5 1 ≤ a < b ≤ 10 9 1 ≤ a < b ≤ 10 9 Example Input: 3 3 5 4 9 5 8 Output: 2 Solution - Step -1 take input in a vector as a pair first element is ending time ans second element is starting time Step -2 sort the vector in increasing order because we will watch that movie which is ending first. Step -3 iterate over vector and calculate ans .           follow code below-