# Algorithms: Find the Symmetric Difference in Swift

Hey guys Leo here,

Today we will start a series in this blog called: Algorithms, the Final Frontier. We'll follow the interview prep series from free code camp.

The first challenge: Challenge Here

The problem: Given two sets (for example set A = {1, 2, 3} and set B = {2, 3, 4}), the mathematical term "symmetric difference" of two sets is the set of elements which are in either of the two sets, but not in both (A △ B = C = {1, 4}).

I could came to this answer:

```
var a1 = [1,2,3,4]
var a2 = [5,6,7,8,13]
var a3 = [9,10,11,12,13,13]
func symmetricDiff(arrays: [[Int]]) -> [Int] {
var resultDict : [Int:Int] = [:]
for x in 0..<arrays.count {
let setTemp = Set<Int>(arrays[x])
for value in setTemp {
if resultDict[value] != nil {
resultDict[value] = resultDict[value]! + 1
} else {
resultDict[value] = 1
}
}
}
return Array<Int>(resultDict.filter({ (element) -> Bool in
element.value == 1
}).keys)
}
print(symmetricDiff(arrays: [a1,a2,a3]))
```

**OR**

A more Swiftly way :

```
func symmetricDiffSwiftly(arrays: [[Int]]) -> [Int] {
var finalSet = Set<Int>()
arrays.forEach { array in
finalSet = finalSet.symmetricDifference(array)
}
return Array<Int>(finalSet)
}
```

Pretty straightforward, no?

Any feedback will be appreciated! Thanks all!

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