Inverted Index for Array

Array+InvertedIndexExtension.swift

extension Array where Element : Comparable {
    var invertedIndexes: [(index: Index, value: Element)] {
        var res = [(index: Index, value: Element)]()

        for (k, v) in enumerated() {
            res.append((index: k, value: v))
        }
        return res
    }
}


// Usage
let invertedIndexes = A.invertedIndexes.sorted { $0.value < $1.value }

// Prints
// [(index: 3, value: 1), (index: 2, value: 2), (index: 1, value: 3), (index: 0, value: 4)]