The divide$-$and$-$conquer approach is an efficient technique for solving complex problems in computer science. To find the largest item in a list of n items using this approach, the list is divided into two halves, the largest item in each half is found recursively, and the largest of the two is returned as the overall largest item. This approach has a time complexity of O$($nlogn$),$ which is better than the O$($n$^2)$ time complexity of a naive approach but not as efficient as the O$($n$)$ time complexity of linear search algorithms. However, linear search algorithms can be less efficient in some cases, such as when the list is not sorted. The divide$-$and$-$conquer approach is useful for solving a variety of problems, and its time complexity can be analyzed using recurrence relations.