# Leetcode: Binary Search

Binary Search Similar Problems:

Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1.

Example 1:

```Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4
```

Example 2:

```Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 does not exist in nums so return -1
```

Note:

1. You may assume that all elements in nums are unique.
2. n will be in the range [1, 10000].
3. The value of each element in nums will be in the range [-9999, 9999].

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

• Solution:
```// Blog link: https://code.dennyzhang.com/binary-search
// Basic Ideas:
// Complexity: Time O(log(n)), Space O(1)
func search(nums []int, target int) int {
var m int
l, r := 0, len(nums)-1
for l<=r {
m = l + (r-l)/2
if nums[m] == target { return m }
if nums[m] > target {
r = m-1
} else {
l = m+1
}
}
return -1
}
```

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