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[Hacker Rank] Interview Preparation Kit: Arrays: New Year Chaos. Solved ✅.
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‎docs/hackerrank/interview_preparation_kit/arrays/new_year_chaos-solution-notes.md

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# [Arrays: New Year Chaos](https://www.hackerrank.com/challenges/new-year-chaos)
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Determine how many bribes took place to get a queue into its current state.
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- Difficulty: ` #medium `
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- Category: ` #ProblemSolvingBasic `
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## Solution sources
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- This solution focuses on "who were bribed" and counts his displacements with
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respect to those who bribed him
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(they have original position numbers greater than this one in front of him):
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[Solution to HackerRank's New Year Chaos in Python](https://csanim.com/tutorials/hackerrank-solution-new-year-chaos)
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- This solution focuses on the expected positions and compares whether the "briber"
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is ahead in line: <https://www.youtube.com/watch?v=LgszjFykAbE>

‎docs/hackerrank/interview_preparation_kit/arrays/new_year_chaos.md

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# [Arrays: New Year Chaos](https://www.hackerrank.com/challenges/new-year-chaos)
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Determine how many bribes took place to get a queue into its current state.
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- Difficulty: ` #medium `
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- Category: ` #ProblemSolvingBasic `
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It is New Year's Day and people are in line for the Wonderland rollercoaster ride.
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Each person wears a sticker indicating their initial position in
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the queue from ` 1 ` to ` n `.
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Any person can bribe the person directly in front of them to swap positions,
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but they still wear their original sticker. One person can bribe at most two others.
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Determine the minimum number of bribes that took place to get
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to a given queue order.
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Print the number of bribes, or, if anyone has bribed more than two people,
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print ` Too chaotic `.
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## Example
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$ q = [1, 2, 3, 4, 5, 6, 7, 8] $
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If person ` 5 ` bribes person ` 4 `, the queue will look like this:
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$ [1, 2, 3, 5, 4, 6, 7, 8] $. Only ` 1 ` bribe is required. Print ` 1 `.
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$ q = [4, 1, 2, 3] $
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Person ` 4 ` had to bribe ` 3 ` people to get to the current position.
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Print `Too chaotic`.
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## Function Description
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Complete the function minimumBribes in the editor below.
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minimumBribes has the following parameter(s):
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- `int q[n]`: the positions of the people after all bribes
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## Returns
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- No value is returned. Print the minimum number of bribes necessary or
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` Too chaotic ` if someone has bribed more than people.
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## Input Format
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The first line contains an integer ` t `, the number of test cases.
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Each of the next ` t ` pairs of lines are as follows:
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- The first line contains an integer ` t `, the number of people in the queue
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- The second line has `n` space-separated integers describing the
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final state of the queue.
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## Constraints
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- $ 1 \leq t \leq 10 $
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- $ 1 \leq n \leq 10^5 $
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## Subtasks
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For `60%` score $ 1 \leq t \leq 10^3 $
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For `100%` score $ 1 \leq t \leq 10^5 $
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## Sample Input
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```text
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STDIN Function
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----- --------
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2 t = 2
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5 n = 5
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2 1 5 3 4 q = [2, 1, 5, 3, 4]
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5 n = 5
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2 5 1 3 4 q = [2, 5, 1, 3, 4]
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```
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## Sample Output
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```text
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3
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Too chaotic
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```
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## Explanation
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### Test Case 1
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The initial state:
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```mermaid
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flowchart LR
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A[Ride!]:::first
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1([1])
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2([2])
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3([3])
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4([4])
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5([5])
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A ~~~ 1
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1 -.- 2
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2 -.- 3
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3 -.- 4
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4 -.- 5
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classDef default color:#000,fill:#FFE195,stroke:#333,stroke-width:4px;
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classDef first fill:#9FBCE8
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classDef emphasys fill:#FEB130
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```
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After person `5` moves one position ahead by bribing person `4`:
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```mermaid
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flowchart LR
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A[Ride!]:::first
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1([1])
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2([2])
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3([3])
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4([4]):::emphasys
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5([5]):::emphasys
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A ~~~ 1
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1 -.- 2
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2 -.- 3
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3 -.- 5
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5 -.- 4
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classDef default color:#000,fill:#FFE195,stroke:#333,stroke-width:4px;
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classDef first fill:#9FBCE8
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classDef emphasys fill:#FEB130
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```
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Now person `5` moves another position ahead by bribing person `3`:
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```mermaid
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flowchart LR
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A[Ride!]:::first
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1([1])
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2([2])
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3([3]):::emphasys
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4([4])
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5([5]):::emphasys
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A ~~~ 1
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1 -.- 2
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2 -.- 5
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5 -.- 3
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3 -.- 4
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classDef default color:#000,fill:#FFE195,stroke:#333,stroke-width:4px;
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classDef first fill:#9FBCE8
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classDef emphasys fill:#FEB130
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```
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And person `2` moves one position ahead by bribing person `3`:
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```mermaid
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flowchart LR
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A[Ride!]:::first
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1([1]):::emphasys
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2([2]):::emphasys
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3([3])
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4([4])
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5([5])
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A ~~~ 2
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2 -.- 1
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1 -.- 5
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5 -.- 3
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3 -.- 4
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classDef default color:#000,fill:#FFE195,stroke:#333,stroke-width:4px;
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classDef first fill:#9FBCE8
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classDef emphasys fill:#FEB130
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```
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So the final state is `2, 1, 5, 3, 4` after three bribing operations.
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### Test Case 2
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No person can bribe more than two people, yet it appears person `5` has done so.
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It is not possible to achieve the input state.

‎src/hackerrank/interview_preparation_kit/arrays/new_year_chaos.test.ts

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import { describe, expect, it } from '@jest/globals';
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import { logger as console } from '../../../logger';
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import { minimumBribesTransform, TOO_CHAOTIC_ERROR } from './new_year_chaos';
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const TEST_CASES = [
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{ title: 'Test Case 0-0', input: [2, 1, 5, 3, 4], expected: 3 },
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{
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title: 'Test Case 0-1',
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input: [2, 5, 1, 3, 4],
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expected: TOO_CHAOTIC_ERROR
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},
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{
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title: 'Test Case 1-1',
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input: [5, 1, 2, 3, 7, 8, 6, 4],
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expected: TOO_CHAOTIC_ERROR
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},
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{ title: 'Test Case 1-2', input: [1, 2, 5, 3, 7, 8, 6, 4], expected: 7 },
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{ title: 'Test Case 2', input: [1, 2, 5, 3, 4, 7, 8, 6], expected: 4 }
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];
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describe('new_year_chaos', () => {
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it('minimumBribes Test Cases', () => {
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expect.assertions(5);
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TEST_CASES.forEach((value) => {
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const answer = minimumBribesTransform(value.input);
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console.debug(
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`minimumBribesTransform(${value.input}) solution found: ${answer}`
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);
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expect(answer).toStrictEqual(value.expected);
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});
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});
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});

‎src/hackerrank/interview_preparation_kit/arrays/new_year_chaos.ts

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/**
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* @link Problem definition [[docs/hackerrank/interview_preparation_kit/arrays/new_year_chaos.md]]
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*/
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export const TOO_CHAOTIC_ERROR = 'Too chaotic';
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export function minimumBribes(q: number[]): number {
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let bribes = 0;
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let i = 0;
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q.forEach((value) => {
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const position = i + 1;
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if (value - position > 2) {
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throw new Error(TOO_CHAOTIC_ERROR);
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}
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const fragment = q.slice(Math.max(value - 2, 0), i);
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fragment.forEach((k) => {
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if (k > value) {
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bribes += 1;
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}
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});
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i += 1;
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});
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return bribes;
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}
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export function minimumBribesTransform(queue: number[]): number | string {
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try {
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return minimumBribes(queue);
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} catch (e) {
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return TOO_CHAOTIC_ERROR;
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}
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}
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export default { minimumBribes, minimumBribesTransform, TOO_CHAOTIC_ERROR };

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