Swift Pascal Triangle Recursive Solution (not optimized)

Pascal.swift

import Foundation

func solve(_ numRows: Int, _ result: [[Int]]?) -> [[Int]] {
    guard numRows > 0 else {
        return []
    }
    
    var tmp = [[Int]]()
    var tmpIndex = 0
    
    if let result = result {
        tmp = result
        tmpIndex = result.count + 1
    } else {
        tmpIndex += 1
    }
    
    if tmpIndex == 1 { tmp.append([1]) }
        
    if tmpIndex > 1 {
        var row = [Int]()
        for i in 0...tmpIndex {
            if i == 0 { row.append(1) }
            if i == (tmpIndex - 1) { row.append(1) }
            if i > 0 && i < tmpIndex - 1 { row.append(tmp[tmpIndex-2][i-1] + tmp[tmpIndex-2][i])}
        }
        tmp.append(row)
    }
    
    if numRows == tmp.count {
        return tmp
    } else {
        return solve(numRows, tmp)
    }
    
}

For a better presentation of the result you can use the following code:

let rowNumber = 10
print("Pascal Triangle for row \(rowNumber) is: ")
let pt = solve(rowNumber, nil)
for row in pt {
    print(row)
}