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 targetexists, 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].

class Solution {

public:

    int search(vector<int>& nums, int target) {

        int len = nums.size();

        int l = 0, r = len-1;

        while (l <= r) {

            int m = l + (r - l) / 2;

            if (nums[m] == target) return m;

            else if (nums[m] > target) r = m - 1;

            else l = m + 1;

        }

        return -1;

    }

};