LongestSubstring.kt

//Finding the length of the longest substring without repeating characters
//Solution
// Iterate through an array, evaluating if new substring should be the max substring
//Time complexity is O(n)..since we're iterating through an array once
//Space complexity is constant
class Solution {
   fun lengthOfLongestSubstring(str: String): Int{
        val map: HashMap<Char, Int> = hashMapOf()
        var max = 0
     // last repeat of any character
        var lastRepeat = -1
        
        str.forEachIndexed{j, value ->
            var lOccur = map.get(value)
            if(lOccur != null){
                lastRepeat = maxOf(lastRepeat, lOccur)
            }
            max = maxOf(max, j - lastRepeat)
            map.put(value, j)
        }
        return max
    }
    
}