Leetcode 3. Longest Substring Without Repeating Characters (Time limit exceeded)

awdawd.swift

class Solution {
    func lengthOfLongestSubstring(_ s: String) -> Int {
        guard s != "" else {
            return 0
        }
        
        let arr = Array(s)
        var resStr: String = "\(arr[0])"
        var tempStr: String = "\(arr[0])"
        
        for i in 0 ..< arr.count-1 {
            tempStr = "\(arr[i])"
            for j in i+1 ..< arr.count {
                if tempStr.firstIndex(of: arr[j]) == nil { // 다른 문자
                    tempStr += "\(arr[j])"
                    if tempStr.count > resStr.count {
                        resStr = tempStr
                    }
                }else{
                    break
                }
            }
        }
        print("The answer is \"\(resStr)\", with the length of \(resStr.count).")
        return resStr.count
    }
}