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27 lines
726 B
27 lines
726 B
3 weeks ago
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/**
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* 加权随机选取
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*/
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export class WeightedPick {
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/**
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* 按 weight 加权随机一项；weight≤0 不参与
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* @param list 候选列表
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*/
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static pick<T extends { weight?: number }>(list: T[]): T | null {
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if (!list?.length) return null;
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let total = 0;
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for (const x of list) {
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const w = Number(x.weight) || 0;
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if (w > 0) total += w;
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}
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if (total <= 0) return null;
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let r = Math.random() * total;
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for (const x of list) {
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const w = Number(x.weight) || 0;
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if (w <= 0) continue;
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r -= w;
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if (r <= 0) return x;
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}
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return list[list.length - 1] ?? null;
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}
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}
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