42 lines
1.4 KiB
JavaScript
42 lines
1.4 KiB
JavaScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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/**
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* Takes a sorted array and a function p. The array is sorted in such a way that all elements where p(x) is false
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* are located before all elements where p(x) is true.
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* @returns the least x for which p(x) is true or array.length if no element fullfills the given function.
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*/
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export function findFirst(array, p) {
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let low = 0, high = array.length;
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if (high === 0) {
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return 0; // no children
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}
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while (low < high) {
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let mid = Math.floor((low + high) / 2);
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if (p(array[mid])) {
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high = mid;
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}
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else {
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low = mid + 1;
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}
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}
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return low;
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}
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export function binarySearch(array, key, comparator) {
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let low = 0, high = array.length - 1;
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while (low <= high) {
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const mid = ((low + high) / 2) | 0;
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const comp = comparator(array[mid], key);
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if (comp < 0) {
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low = mid + 1;
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}
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else if (comp > 0) {
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high = mid - 1;
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}
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else {
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return mid;
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}
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}
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return -(low + 1);
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}
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