Question

How to find a pair with maximum product from int array in Swift

Answer 1

import Foundation

func maxProductPair(_ nums: [Int]) -> (Int, Int) {
    precondition(nums.count >= 2, "Need at least two numbers")

    var max1 = Int.min
    var max2 = Int.min
    var min1 = Int.max
    var min2 = Int.max

    for n in nums {
        // Track two largest
        if n > max1 {
            max2 = max1
            max1 = n
        } else if n > max2 {
            max2 = n
        }

        // Track two smallest
        if n < min1 {
            min2 = min1
            min1 = n
        } else if n < min2 {
            min2 = n
        }
    }

    return (max1 * max2 >= min1 * min2) ? (max1, max2) : (min1, min2)
}


let nums = [3, 9, 1, 3, 7, 0, 4]

let (a, b) = maxProductPair(nums)

print("Pair: (\(a), \(b)), product = \(a * b)")




/*
run:

Pair: (9, 7), product = 63

*/

 

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