Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | 2x 2x 2x 3x 2x 1x 1x 1x 1x 1x 1x 2x 2x 3x 1x 2x 1x 1x 1x 3x 1x 1x 1x 3x 1x 2x | // @src https://basarat.gitbook.io/algorithms/basics/tips#random-numbers
export const random = (min: number, max: number): number => {
if (!window.crypto) {
return ~~(Math.random() * (max - min) + min);
} else {
// eslint-disable-next-line compat/compat
const randomBuffer = new Uint32Array(1);
window.crypto.getRandomValues(randomBuffer);
const randomNumber = randomBuffer[0] / (0xffffffff + 1);
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(randomNumber * (max - min + 1)) + min;
}
};
// @src https://github.com/trekhleb/javascript-algorithms/blob/master/src/algorithms/statistics/weighted-random/weightedRandom.js
export const weightedRandom = <Item>(items: Item[], weights: number[]): Item | void => {
if (items.length !== weights.length) {
throw new Error("Items and weights must be of the same size");
}
if (!items.length) {
throw new Error("Items must not be empty");
}
// Preparing the cumulative weights array.
// For example:
// - weights = [1, 4, 3]
// - cumulativeWeights = [1, 5, 8]
const cumulativeWeights: number[] = [];
for (let i = 0; i < weights.length; i += 1) {
// eslint-disable-next-line security/detect-object-injection
cumulativeWeights[i] = weights[i] + (cumulativeWeights[i - 1] || 0);
}
// Getting the random number in a range of [0...sum(weights)]
// For example:
// - weights = [1, 4, 3]
// - maxCumulativeWeight = 8
// - range for the random number is [0...8]
const maxCumulativeWeight = cumulativeWeights[cumulativeWeights.length - 1];
const randomNumber = random(0, maxCumulativeWeight);
// Picking the random item based on its weight.
// The items with higher weight will be picked more often.
for (let itemIndex = 0; itemIndex < items.length; itemIndex += 1) {
// eslint-disable-next-line security/detect-object-injection
if (cumulativeWeights[itemIndex] >= randomNumber) {
// eslint-disable-next-line security/detect-object-injection
return items[itemIndex];
}
}
};
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