23 lines
740 B
Markdown
23 lines
740 B
Markdown
### binarySearch
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Use recursion. Similar to `Array.indexOf()` that finds the index of a value within an array. The two differences being
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1. Operation only works with sorted arrays
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2. Offers a major performance boost when compared to a linear search or `Array.indexOf()`
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```js
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const binarySearch = (arr, val, start = 0, end = arr.length - 1) => {
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if (start > end) return -1;
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const mid = Math.floor((start + end) / 2);
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return (arr[mid] > val)
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? binarySearch(arr, val, start, mid - 1)
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: (arr[mid] < val)
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? binarySearch(arr, val, mid + 1, end)
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: mid
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}
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```
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```js
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binarySearch([1, 4, 6, 7, 12, 13, 15, 18, 19, 20, 22, 24], 6); // 2
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binarySearch([1, 4, 6, 7, 12, 13, 15, 18, 19, 20, 22, 24], 21); // -1
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```
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