Missing integer variation - O(n) solution needed [closed]

Answer 1

Sweet Swift version. 100% correct

public func solution(inout A : [Int]) -> Int {
    //Create a Hash table
    var H = [Int:Bool]()
    // Create the minimum possible return value
    var high = 1
    //Iterate
    for i in 0.. high ? A[i] : high
        // Fill hash table
        if (A[i] > 0){
            H[A[i]] = true
        }
    }
    // iterate through possible values on the hash table
    for j in 1...high {
        // If you could not find it on the hash, return it
        if H[j] != true {
            return j
        } else {
            // If you went through all values on the hash
            // and can't find it, return the next higher value
            // e.g.: [1,2,3,4] returns 5
            if (j == high) {
                return high + 1
            }
        }
    }
    return high
}