Implement World Rankings

[lemonpole]

Might have to just use ELO. There's a lot of different ranking systems like HLTV, Valve, etc., each with their own algorithms.

• https://en.wikipedia.org/wiki/Elo_rating_system

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function calculateExpectedScore(ratingA: number, ratingB: number): number {
  return 1 / (1 + Math.pow(10, (ratingB - ratingA) / 400));
}

function calculateNewRating(rating: number, expectedScore: number, actualScore: number, kFactor: number): number {
  return rating + kFactor * (actualScore - expectedScore);
}

// Example usage:
let player1Rating = 1500;
let player2Rating = 1600;
let kFactor = 32;

let expectedScore1 = calculateExpectedScore(player1Rating, player2Rating);
let expectedScore2 = calculateExpectedScore(player2Rating, player1Rating);

// Assume player 1 wins
let player1NewRating = calculateNewRating(player1Rating, expectedScore1, 1, kFactor);
let player2NewRating = calculateNewRating(player2Rating, expectedScore2, 0, kFactor);

console.log("Player 1 new rating:", player1NewRating);
console.log("Player 2 new rating:", player2NewRating);

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• https://gist.github.com/bastienrobert/8aeb260d3691809abac8ffb1a25a6cd8