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Add comments to binarySearch function.

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This commit is contained in:
Oleksii Trekhleb 2018-12-04 08:04:24 +02:00
parent 039555f00b
commit 243be8f2d1
1 changed files with 7 additions and 0 deletions
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7
src/algorithms/search/binary-search/binarySearch.js
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@ -10,12 +10,18 @@ import Comparator from '../../../utils/comparator/Comparator';
*/ */
export default function binarySearch(sortedArray, seekElement, comparatorCallback) { export default function binarySearch(sortedArray, seekElement, comparatorCallback) {
// Let's create comparator from the comparatorCallback function.
// Comparator object will give us common comparison methods like equal() and lessThen().
const comparator = new Comparator(comparatorCallback); const comparator = new Comparator(comparatorCallback);
// These two indices will contain current array (sub-array) boundaries.
let startIndex = 0; let startIndex = 0;
let endIndex = sortedArray.length - 1; let endIndex = sortedArray.length - 1;
// Let's continue to split array until boundaries are collapsed
// and there is nothing to split anymore.
while (startIndex <= endIndex) { while (startIndex <= endIndex) {
// Let's calculate the index of the middle element.
const middleIndex = startIndex + Math.floor((endIndex - startIndex) / 2); const middleIndex = startIndex + Math.floor((endIndex - startIndex) / 2);
// If we've found the element just return its position. // If we've found the element just return its position.
@ -33,5 +39,6 @@ export default function binarySearch(sortedArray, seekElement, comparatorCallbac
} }
} }
// Return -1 if we have not found anything.
return -1; return -1;
} }