class Solution{
public:
int search(std::vector<int> nums, int target){
int left = 0, right = nums.size()-1;
while (left <= right){
int mid = left + (right-left)/2;
if (nums[mid] == target) return mid;
else if (nums[mid] > target) right = mid-1;
else left = mid+1;
}
return -1;
}
};