Algorithms-With-Swift/Array/TwoSumProblem.swift at master · athakur3/Algorithms-With-Swift · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
//
//  TwoSumProblem.swift
//  Algorithms With Swift
//
//  Created by Akshansh Thakur on 21/08/20.
//  Copyright © 2020 Akshansh Thakur. All rights reserved.
//

// Approch 1

func checkTwoSum(array: [Int], sum: Int) -> (Bool, Int?, Int?) {

    var i = 0
    var j = array.count - 1

    while j > i {
        switch array[i] + array[j] {
        case (sum + 1)..<Int.max:
            j -= 1
        case Int.min..<sum:
            i += 1
        case sum:
            return (true, array[i], array[j])
        default:
            return (false, nil, nil)
        }
    }
    return (false, nil, nil)
}

// Approch 2
func checkTwoSum(array:[Int],sum:Int) -> (Bool,Int?,Int?){
    var dic:[Int:Int] = [:]

    for i in array{
        if dic[i] != nil{
            return (true,sum-i,i)
        }else{
            dic[sum-i] = i
        }
    }

    return (false,nil,nil)
}