Skip to main content

Replace for X codechef October long challenge solution | codechef October long challenge editorial

 Replace for X  codechef October long challenge solution -

This Problem is taken from CodeChef October long challenge.

Problem Statement-

You are given an array of N integers A1,A2,,AN and three more integers X,p, and k.

An operation on the array is defined to be: replace the k-th smallest integer in the array with any integer you want.

Output the minimum number of operations you must perform on the array (possibly 0 operations) to make the p-th smallest element of the array equal to X. If it is impossible to do so output 1.

Note: the k-th smallest number in an array is the k-th number from the left when the array is sorted in non-decreasing order.

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 line of each test case contains four integers N,X,p,k respectively.
  • The second line contains N space-separated integers A1,A2,,AN.

Output

For each test case, print a single line containing one integer ― the minimum number of operations you must perform to make X the p-th smallest element or 1 if its impossible to do so.

Constraints

  • 1T100
  • 1p,kN
  • 0X109
  • The sum of N over all test cases does not exceed 4105
  • 0Ai109 for each valid i

Subtasks

Subtask #1 (10 points): N5

Subtask #2 (40 points): The sum of N over all test cases does not exceed 3103

Subtask #3 (50 points): Original constraints

Example Input

2
5 4 3 4
4 9 7 0 8
2 25 1 2
100 20

Example Output

1
-1

Explanation

Example case 1:

  • We can perform one operation in the array. Take the k-th smallest integer of the current array (which is 8 in this case) and replace it with 0. The array then becomes [4,9,7,0,0] which now makes 4 as the 3rd smallest number of the array.

Example case 2:

  • It is impossible to make 25 as the smallest number of the array.





Solution-

SOlution-
Since a note is mentioned in question that 
Note: the k-th smallest number in an array is the k-th number from the left when the array is sorted in non-decreasing order.
So first of all we will sort our array/vector in non-decreasing order so that we can find kth smalles number.

then  p=p-1;
      k=k-1;
because index is starting from 0 in my code so i did previous step.
I have written a solution function which return minumum number of operation reequired.
Now Let's jump into logic.
1-first of all i will check is(v[p]==X) if it is true i will simply return 0 because in this case i already have my answer.
2-now i will maintain a count variable which count total operation required.
3-Main logic start from here since out array is sorted till now so  we have three choices from here if(k>p),if(k<p) and if(k==p) and 
in every 3 case these 3 case also contain two-two cases if(v[p]<x) and if(v[p]>x).

4- if(k>p) and if(v[p]<x) in this case we never reach to final solution so i will return -1 in this case.
if (k>p) && v[p]> x in this case i can reach to my solution and i will try to add some smaller value at k so that i can shift 
value at p toward k ans every time i increase my value by one.
5- same if (k<p) this case is totally opposite of case 4.
6- if (k==p)
in this case i can reach to my solution 
if(v[p]>x) i have to shift pth value to left  
and if(v[p]<x) i will shift pth value  to right 
and count ans.
finllay i return ans which tells minimum way to get final solution.
  code of this problem 

Comments

Popular posts from this blog

Vaccine Distribution Codechef December Long challenge solution 2020

 Vaccine Distribution  Codechef December Long challenge solution 2020- This Problem vaccine distribution is taken from December long challenge 2020. lets read problem statement. Problem statement- Finally, a COVID vaccine is out on the market and the Chefland government has asked you to form a plan to distribute it to the public as soon as possible. There are a total of  N N  people with ages  a 1 , a 2 , … , a N a 1 , a 2 , … , a N . There is only one hospital where vaccination is done and it is only possible to vaccinate up to  D D  people per day. Anyone whose age is  ≥ 80 ≥ 80  or  ≤ 9 ≤ 9  is considered to be  at risk . On each day, you may not vaccinate both a person who is at risk and a person who is not at risk. Find the smallest number of days needed to vaccinate everyone. Input The first line of the input contains a single integer  T T  denoting the number of test cases. The description of  T T  test cases follows. The first line of each test case contains two space-separ

Codechef February long challenge solution 2021

   Codechef February  long challenge solution 2021- Hey guys Welcome Again, A small update CodeChef February  long challenge solution 2021 starting from 1st week of beb  2021 . Codechef long challenge is one of the popular contests of CodeChef you should participate in codechef Feb  long challenge.This is first contest of codechef in 2021 so good luck. And wish you happy new year. Contest link- https://www.codechef.com/FEB21/?itm_medium=navmenu&itm_campaign=FEB21 I will post the solution after Contest.Stay tuned. About CodeChef  February  long challenge solution 2021: CodeChef Long Challenge is a 10-day monthly coding contest where you can show off your computer programming skills. The significance being - it gives you enough time to think about a problem, try different ways of attacking the problem, read the concepts etc. If you’re usually slow at solving problems and have ample time at hand, this is ideal for you. We also put in a lot of efforts in getting quality problems, w

Merge Two sorted array Without Extra Space

Problem statement-  Given two sorted arrays arr1[] and arr2[] of sizes N and M in non-decreasing order. Merge them in sorted order without using any extra space. Modify arr1 so that it contains the first N elements and modify arr2 so that it contains the last M elements.    Example 1: Input:  N = 4, arr1[] = [1 3 5 7]  M = 5, arr2[] = [0 2 6 8 9] Output:  arr1[] = [0 1 2 3] arr2[] = [5 6 7 8 9] Explanation: After merging the two  non-decreasing arrays, we get,  0 1 2 3 5 6 7 8 9.   Example 2: Input:  N = 2, arr1[] = [10, 12]  M = 3, arr2[] = [5 18 20] Output:  arr1[] = [5 10] arr2[] = [12 18 20] Explanation: After merging two sorted arrays  we get 5 10 12 18 20. Your Task: You don't need to read input or print anything. You only need to complete the function merge() that takes arr1, arr2, N and M as input parameters and modifies them in-place so that they look like the sorted merged array when concatenated. Expected Time Complexity:  O((n+m) log(n+m)) Expected Auxilliary Space: O(1