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4fa28c04ee
* return -1 if target is not in array * return -1 if target is not in array (python) * <= in binary search while loop
27 lines
839 B
JavaScript
27 lines
839 B
JavaScript
function binarySearch(arr, target) {
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let left = 0;
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let right = arr.length - 1;
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while (left <= right) {
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let mid = left + Math.floor((right - left) / 2);
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if (arr[mid] === target) {
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return mid;
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}
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if (arr[mid] < target) {
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left = mid + 1;
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} else {
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right = mid - 1;
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}
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}
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return -1;
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}
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console.log(binarySearch([1, 2, 3, 10], 1) === 0)
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console.log(binarySearch([1, 2, 3, 10], 2) === 1)
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console.log(binarySearch([1, 2, 3, 10], 3) === 2)
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console.log(binarySearch([1, 2, 3, 10], 10) === 3)
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console.log(binarySearch([1, 2, 3, 10], 9) === -1)
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console.log(binarySearch([1, 2, 3, 10], 4) === -1)
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console.log(binarySearch([1, 2, 3, 10], 0) === -1)
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console.log(binarySearch([1, 2, 3, 10], 11) === -1)
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console.log(binarySearch([5, 7, 8, 10], 3) === -1)
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