Skip to main content

Point Of Impact Codechef January 2021 solution || Point Of Impact codechef january 2021 editorial

 Point Of Impact Codechef January 2021 solution || Point Of Impact codechef january 2021 editorial -

Problem statement-

You are playing a Billiards-like game on an N×N table, which has its four corners at the points {(0,0),(0,N),(N,0), and (N,N)}. You start from a coordinate (x,y)(0<x<N,0<y<N) and shoot the ball at an angle 45 with the horizontal. On hitting the sides, the ball continues to move with the same velocity and ensuring that the angle of incidence is equal to the angle of reflection with the normal, i.e, it is reflected with zero frictional loss. On hitting either of the four corners, the ball stops there and doesn’t move any further.

Find the coordinates of the point of collision, when the ball hits the sides for the Kth time. If the ball stops before hitting the sides K times, find the coordinates of the corner point where the ball stopped instead.

Input:

  • The first line of the input contains an integer T, the number of testcases.
  • Each testcase contains a single line of input, which has four space separated integers - NKxy, denoting the size of the board, the number of collisions to report the answer for, and the starting coordinates.

Output:

For each testcase, print the coordinates of the ball when it hits the sides for the Kth time, or the coordinates of the corner point if it stopped earlier.

Constraints

  • 1T105
  • 2N109
  • 1K109

Subtasks

  • 30 points : Sum of K over all test cases 107
  • 70 points : Original constraints.

Sample Input:

2
5 5 4 4
5 2 3 1

Sample Output:

5 5
3 5

Explanation:

  • Sample Case 1 :

We are given a 5 by 5 board. We shoot the ball from coordinates (4,4), and we need to find its coordinates after it has collided with sides 5 times. However, after shooting, the ball goes directly to the corner (5,5), and stops there. So we report the coordinates (5,5).

fig1

  • Sample Case 2 :

We are given a 5 by 5 board. We shoot the ball from the coordinates (3,1), and we need to find its coordinates after it has collided with the sides twice. After shooting, it first hits the right side at (5,3), and then the top side at (3,5). So, we report (3,5).

fig1

Solution -

Actually this is a simple problem you need little bit of maths knowledge to solve this problem.
You have to find 4 points on where the ball is striking. the fact is that the ball can strike a maximum of 4 different point and after first 4 point  point of impact will start repeating.

You need to find 4 points of impact and ball direction(clockwise / anticlockwise) .ans differ according to ball direction.
Here is my code. look it and check how i implemented this logic.


Join telegram channel for code and editorial.-https://t.me/competitiveProgrammingDiscussion

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

Playlist CSES Problems set solution | searching ans sorting with code and explanation

 Playlist CSES Problems set solution- Playlist problem statement- Time limit:  1.00 s   Memory limit:  512 MB You are given a playlist of a radio station since its establishment. The playlist has a total of  n n  songs. What is the longest sequence of successive songs where each song is unique? Input The first input line contains an integer  n n : the number of songs. The next line has  n n  integers  k 1 , k 2 , … , k n k 1 , k 2 , … , k n : the id number of each song. Output Print the length of the longest sequence of unique songs. Constraints 1 ≤ n ≤ 2 ⋅ 10 5 1 ≤ n ≤ 2 ⋅ 10 5 1 ≤ k i ≤ 10 9 1 ≤ k i ≤ 10 9 Example Input: 8 1 2 1 3 2 7 4 2 Output:5 Playlist CSE S Problems set solution- Step -1 store value in hashmap so that we can check that song played before or not. step -2 make two-pointer i and j if v[i] has occurred earlier remove all element till v[i] and update ans.new length will be (i-j). Step 3- if v[i]  not occurred simply update ans by one.