Junior — Middle
What methods can be used for quick element search in a sorted array, minimizing time costs?
sobes.tech AI
Answer from AI
For quick search in a sorted array, binary search algorithm is usually used. It minimizes time costs by working in O(log n) time, where n is the size of the array.
Idea of binary search:
- Compare the target element with the middle element of the array.
- If they are equal, the element is found.
- If the target is less, repeat the search in the left half.
- If greater, in the right half.
In iOS (Swift), you can use the binarySearch method or implement it yourself.
Example in Swift:
func binarySearch<T: Comparable>(_ array: [T], target: T) -> Int? {
var low = 0
var high = array.count - 1
while low <= high {
let mid = (low + high) / 2
if array[mid] == target {
return mid
} else if array[mid] < target {
low = mid + 1
} else {
high = mid - 1
}
}
return nil
}
let sortedArray = [1, 3, 5, 7, 9]
if let index = binarySearch(sortedArray, target: 5) {
print("Element found at position \(index)")
} else {
print("Element not found")
}