Lista

def fill_blanks(s, l):
    n = len(s)
    qs = 0
    for i in range(n):
        qs += s[i] == '?'
    if qs == 0: return s
    if l == "":
        if s[0] == '?': s[0] = '1'
        for i in range(1, n):
            if s[i] == '?': s[i] = '0'
        return s
    if len(l) > len(s): return ""
    if len(l) < len(s):
        if s[0] == '?': s[0] = '1'
        for i in range(1, n):
            if s[i] == '?': s[i] = '0'
        if int(''.join(s)) <= int(''.join(l)): return ""
        return s
    nines = 0
    for c in l:
        nines += c == '9'
    if nines == n: return ""
    if nines == n-1 and l[0] != '9':
        if s[0] == '?':
            s[0] = str(int(l[0]) + 1)
        elif s[0] <= l[0]:
            return ""
    b = []
    for i in range(n):
        if s[i] == l[i] or s[i] == '?':
            b.append(0)
        else:
            b.append((int(s[i])-int(l[i]))/abs(int(s[i])-int(l[i])))
    qi = []
    for i in range(n):
        if s[i] == '?':
            qi.append(i)
    le = 0
    gr = 0
    while le < n and b[le] != -1: le += 1
    while gr < n and b[gr] != 1: gr += 1
    if gr < le:
        for i in qi:
            if i < gr: s[i] = l[i]
            else: s[i] = '0'
    elif le < gr:
        ti = -1
        for i in qi:
            if i < le and l[i] != '9': ti = i
        if ti == -1: return ""
        for i in qi:
            if i < ti: s[i] = l[i]
            elif i == ti: s[i] = str(int(l[i])+1)
            else: s[i] = '0'
    else:
        s = str(int(''.join(l))+1)
    if int(''.join(s)) <= int(''.join(l)): return ""
    return s

n = int(input())
v = []
l = ""
for i in range(n):
    s = list(input())
    s = fill_blanks(s, l)
    if s == "":
        print("IMPOSSIBLE")
        exit(0)
    v.append(''.join(s))
    l = s
last = -1
for s in v:
    if int(s) <= last:
        print("IMPOSSIBLE")
        exit(0)
    last = int(s)
print(*v, sep="\n")

Test 1

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 2

Group: 2, 3

Verdict: WRONG ANSWER

Test 3

Group: 3

Verdict: WRONG ANSWER

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 3

Verdict: ACCEPTED

Test 9

Group: 3

Verdict: WRONG ANSWER

Test 10

Group: 3

Verdict: ACCEPTED