Day 1 of Advent Code

FindProductOfTwoNumberWithTargetSum1.swift

func findIndexOf(targetSum sum: Int, in inputArray: [Int]) -> (Int,Int) {
    // Output Indices
    var indices: (Int,Int) = (-1, -1)
    // hastable
    var hashTable = [Int:Int]()
    // enumerate it
    for (index, value) in inputArray.enumerated() {
        // check if hastable has complementry value (i.e index)
        if let rightIndex = hashTable[value] {
            indices.0 = index
            indices.1 = rightIndex
            break
        } else {
            // set the key as 'compelementry value'  and value  as 'index'
            hashTable[sum-value] =  index
        }
        
    }
    
    return indices
}

let indicess = findIndexOf(targetSum: 2020, in: inputArray)
print(inputArray[indicess.0] * inputArray[indicess.1])