For problem statement at 0-999/0-99/60-69/65/problemD.txt this is a correct solution, but verifier at 0-999/0-99/60-69/65/verifierD.go ends with case 2 failed: expected
Gryffindor
Hufflepuff
Ravenclaw
Slytherin
got
Hufflepuff
Ravenclaw
Slytherin
input:
14
HHRG??RHS?GSG?
exit status 1 can you fix the verifier? package main

import (
	"bufio"
	"fmt"
	"math/bits"
	"os"
)

type State [4]int

var comb [5][5]int

func compress(mp map[State]struct{}) []State {
	states := make([]State, 0, len(mp))
	if len(mp) == 0 {
		return states
	}
	low := State{1 << 30, 1 << 30, 1 << 30, 1 << 30}
	high := State{-1, -1, -1, -1}
	total := -1
	for st := range mp {
		states = append(states, st)
		sum := 0
		for i := 0; i < 4; i++ {
			if st[i] < low[i] {
				low[i] = st[i]
			}
			if st[i] > high[i] {
				high[i] = st[i]
			}
			sum += st[i]
		}
		if total == -1 {
			total = sum
		}
	}
	var vars []int
	baseSum := 0
	for i := 0; i < 4; i++ {
		if high[i]-low[i] > 1 {
			return states
		}
		if high[i]-low[i] == 1 {
			vars = append(vars, i)
		}
		baseSum += low[i]
	}
	k := total - baseSum
	if k < 0 || k > len(vars) {
		return states
	}
	if comb[len(vars)][k] != len(states) {
		return states
	}
	gen := make([]State, 0, len(states))
	for mask := 0; mask < (1 << len(vars)); mask++ {
		if bits.OnesCount(uint(mask)) != k {
			continue
		}
		ns := low
		for j, idx := range vars {
			if (mask>>j)&1 == 1 {
				ns[idx]++
			}
		}
		if _, ok := mp[ns]; !ok {
			return states
		}
		gen = append(gen, ns)
	}
	return gen
}

func houseIndex(ch byte) int {
	switch ch {
	case 'G':
		return 0
	case 'H':
		return 1
	case 'R':
		return 2
	default:
		return 3
	}
}

func main() {
	for i := 0; i <= 4; i++ {
		comb[i][0] = 1
		comb[i][i] = 1
		for j := 1; j < i; j++ {
			comb[i][j] = comb[i-1][j-1] + comb[i-1][j]
		}
	}

	in := bufio.NewReader(os.Stdin)
	var n int
	var s string
	fmt.Fscan(in, &n, &s)

	states := []State{{0, 0, 0, 0}}

	for i := 0; i < n; i++ {
		next := make(map[State]struct{}, len(states)*4)
		if s[i] == '?' {
			for _, st := range states {
				mn := st[0]
				for j := 1; j < 4; j++ {
					if st[j] < mn {
						mn = st[j]
					}
				}
				for j := 0; j < 4; j++ {
					if st[j] == mn {
						ns := st
						ns[j]++
						next[ns] = struct{}{}
					}
				}
			}
		} else {
			idx := houseIndex(s[i])
			for _, st := range states {
				ns := st
				ns[idx]++
				next[ns] = struct{}{}
			}
		}
		states = compress(next)
	}

	possible := [4]bool{}
	for _, st := range states {
		mn := st[0]
		for j := 1; j < 4; j++ {
			if st[j] < mn {
				mn = st[j]
			}
		}
		for j := 0; j < 4; j++ {
			if st[j] == mn {
				possible[j] = true
			}
		}
	}

	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	names := [4]string{"Gryffindor", "Hufflepuff", "Ravenclaw", "Slytherin"}
	for i := 0; i < 4; i++ {
		if possible[i] {
			fmt.Fprintln(out, names[i])
		}
	}
}