rockPaperScissors.js (8kyu 23)

02 Mar 2019 in about Dev on Algorithm

Codewars 알고리즘 풀이

Problem

You have to return which player won.
- 가위바위보에서 승리한 플레이어를 반환한다.
In case of a draw return Draw!.
- 비겼을 경우, Draw!를 반환한다.

Solution 01

function rockPaperScissors(p1, p2) {
  if (p1 === p2) return 'Draw!';
  
  if (p1 === 'rock' && p2 === 'scissors') {
    return 'Player 1 won!';
  } else if (p1 === 'paper' && p2 === 'rock') {
    return 'Player 1 won!';
  } else if (p1 === 'scissors' && p2 === 'paper') {
    return 'Player 1 won!';
  } else {
    return 'Player 2 won!';
  }
}

rockPaperScissors('rock', 'rock');      // Draw!
rockPaperScissors('scissors', 'rock');  // Player 2 won!
rockPaperScissors('paper', 'rock');     // Player 1 won!
rockPaperScissors('paper', 'paper');    // Draw!

Solution 02

function rockPaperScissors(p1, p2) {
  if (p1 === p2) return 'Draw!';
  
  const rules = {
    rock: 'scissors',
    paper: 'rock',
    scissors: 'paper'
  };
  
  if (rules[p1] === p2) {
    return 'Player 1 won!';
  } else {
    return 'Player 2 won!';
  }
}

rockPaperScissors('rock', 'rock');      // Draw!
rockPaperScissors('scissors', 'rock');  // Player 2 won!
rockPaperScissors('paper', 'rock');     // Player 1 won!
rockPaperScissors('paper', 'paper');    // Draw!

Solution 03

function rockPaperScissors(p1, p2) {
  const rules = {
    rock: 'scissors',
    paper: 'rock',
    scissors: 'paper'
  };
  
  if (p1 === p2) {
    return 'Draw!';
  } else {
    return 'Player ${rules[p1] === p2 ? 1 : 2} won!';
  }
}

rockPaperScissors('rock', 'rock');      // Draw!
rockPaperScissors('scissors', 'rock');  // Player 2 won!
rockPaperScissors('paper', 'rock');     // Player 1 won!
rockPaperScissors('paper', 'paper');    // Draw!

Solution 04

function rockPaperScissors(p1, p2) {
  if (p1 === p2) return 'Draw!';
  
  return `Player ${/rockscissors|scissorspaper|paperrock/.test(p1 + p2) ? 1 : 2} won!`;
}

rockPaperScissors('rock', 'rock');      // Draw!
rockPaperScissors('scissors', 'rock');  // Player 2 won!
rockPaperScissors('paper', 'rock');     // Player 1 won!
rockPaperScissors('paper', 'paper');    // Draw!

정규표현식 (RegExp)
test(): 대응되는 문자열이 있는지 검색하고, true/false를 반환한다.