Commit 644557f

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Merge pull request #9 from anasmak04/master

add binary search

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Lines changed: 2 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -48,6 +48,7 @@`
`48`	`48`	`\| Problem - 44 \| [ swap ](https://github.com/anasmak04/Problem-solving-with-JavaScript/blob/master/problem-44.js) \|`
`49`	`49`	`\| Problem - 45 \| [ max two numbers ](https://github.com/anasmak04/Problem-solving-with-JavaScript/blob/master/problem-45.js) \|`
`50`	`50`	`\| Problem - 46 \| [ Sort an Array without using any built-in functions ](https://github.com/anasmak04/Problem-solving-with-JavaScript/blob/master/problem-46.js) \|`
	`51`	`+\| Problem - 47 \| [ Binary Search ](https://github.com/anasmak04/Problem-solving-with-JavaScript/blob/master/problem-47.js) \|`
`51`	`52`
`52`	`53`
`53`		`-<!-- \| Problem - 47 \| \| -->`
	`54`	`+<!-- \| Problem - 48 \| \| -->`

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`@@ -0,0 +1,35 @@`
	`1`	`+// Given an array of integers nums which is sorted in ascending order,`
	`2`	`+// and an integer target, write a function to search target in nums.`
	`3`	`+// If target exists, then return its index. Otherwise, return -1.`
	`4`	`+// You must write an algorithm with O(log n) runtime complexity.`
	`5`	`+`
	`6`	`+`
	`7`	`+let search = function (nums, target) {`
	`8`	`+ let array = nums.sort(function (a, b) { return a - b });`
	`9`	`+ let firstIndex = 0;`
	`10`	`+ let lastIndex = array.length - 1;`
	`11`	`+ while (firstIndex <= lastIndex) {`
	`12`	`+ let middleIndex = Math.floor((firstIndex + lastIndex) / 2);`
	`13`	`+ if (target == array[middleIndex]) {`
	`14`	`+ return middleIndex`
	`15`	`+ }`
	`16`	`+ if (target < array[middleIndex]) {`
	`17`	`+ lastIndex = middleIndex - 1;`
	`18`	`+ }`
	`19`	`+ else {`
	`20`	`+ firstIndex = middleIndex + 1;`
	`21`	`+ }`
	`22`	`+ }`
	`23`	`+ return -1`
	`24`	`+};`
	`25`	`+`
	`26`	`+// Example 1:`
	`27`	`+`
	`28`	`+// Input: nums = [-1,0,3,5,9,12], target = 9`
	`29`	`+// Output: 4`
	`30`	`+// Explanation: 9 exists in nums and its index is 4`
	`31`	`+// Example 2:`
	`32`	`+`
	`33`	`+// Input: nums = [-1,0,3,5,9,12], target = 2`
	`34`	`+// Output: -1`
	`35`	`+// Explanation: 2 does not exist in nums so return -1`

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