I never removed anyone from my life,
but they all died in the accident of
trust.

Discipline is doing what needs to be done, even if you don't want to do it.

class Solution {
    fun residuePrefixes(s: String): Int {
        val seen = BooleanArray(26)
        var distinct = 0
        var ans = 0

        for (i in s.indices) {
            val idx = s[i] - 'a'
            if (!seen[idx]) {
                seen[idx] = true
                distinct++
            }

            val len = i + 1
            if (distinct == (len % 3)) {
                ans++
            }
        }

        return ans
    }
}