26 lines
896 B
TypeScript
26 lines
896 B
TypeScript
/**
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* Performs a binary search within a specified range.
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* @param begin The starting index of the search range.
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* @param end The ending index of the search range.
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* @param beforeHalf A list of predicates indicating conditions before the midpoint.
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* @returns A tuple containing the indices representing the binary search state: [begin, half, end].
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*/
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export function binSearch(begin: number, end: number, beforeHalf: boolean[]): [number, number, number] {
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const gHalf = () => { return Math.floor((end - begin) / 2) + begin; }
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for (const pred of beforeHalf) {
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const half = gHalf();
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if (pred) {
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// Happens before "half"
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end = half;
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} else {
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begin = half;
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}
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}
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const half = gHalf();
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console.log(`Checking range: [${begin}, ${end}], ${end - begin} objects, mid ${half}`);
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return [begin, half, end];
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}
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