Binary Search

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int r=nums.size()-1;
        int l=0;
         while (l <= r) {
        int m = l + (r - l) / 2;

        // Check if target is present at mid
        if (nums[m] == target)
            return m;

        // If target greater, ignore left half
        if (nums[m] < target)
            l = m + 1;

        // If target is smaller, ignore right half
        else
            r = m - 1;
    }
        return -1;
    }
};