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replace target with arr[mid]

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King
2018-01-05 11:18:01 -05:00
parent fbb292b1ca
commit be08d9f7b1
1 changed files with 4 additions and 5 deletions
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snippets/binarySearch.md
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@ -1,17 +1,16 @@
### binarySearch ### binarySearch
Use recursion to perform a logarithmic search similar to `.indexOf()` that finds the index of a value within an array. The two differences being Use recursion. Similar to `Array.indexOf()` that finds the index of a value within an array. The two differences being
1. Operation only works with sorted arrays 1. Operation only works with sorted arrays
2. Offers a major performance boost when compared to a linear search or `.indexOf()` 2. Offers a major performance boost when compared to a linear search or `Array.indexOf()`
```js ```js
const binarySearch = (arr, val, start = 0, end = arr.length - 1) => { const binarySearch = (arr, val, start = 0, end = arr.length - 1) => {
if (start > end) return -1; if (start > end) return -1;
const mid = Math.floor((start + end) / 2); const mid = Math.floor((start + end) / 2);
const target = arr[mid]; return (arr[mid] > val)
return (target > val)
? binarySearch(arr, val, start, mid - 1) ? binarySearch(arr, val, start, mid - 1)
: (target < val) : (arr[mid] < val)
? binarySearch(arr, val, mid + 1, end) ? binarySearch(arr, val, mid + 1, end)
: mid : mid
} }