Lista

#include <bits/stdc++.h>

typedef long long ll;

#define M 1000000007
#define N (1 << 18)

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<string> v(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i];
    }

    vector<string> ans;

    string cur = v[0];

    for (int i = 0; i < (int)cur.size(); ++i) {
        if (cur[i] == '?') {
            if (i == 0) {
                cur[i] = '1';
            } else {
                cur[i] = '0';
            }
        }
    }

    ans.push_back(cur);

    for (int i = 1; i < n; ++i) {
        if (cur.size() < v[i].size()) {
            // Just make low
            cur = v[i];
            for (int j = 0; j < (int)cur.size(); ++j) {
                if (cur[j] == '?') {
                    if (j == 0) {
                        cur[j] = '1';
                    } else {
                        cur[j] = '0';
                    }
                }
            }

            ans.push_back(cur);
        } else {
            // Improve
            bool gt = false;
            int len = cur.size();
            string orig = v[i];
            for (int j = 0; j < len; ++j) {
                if (v[i][j] != '?') {
                    if (v[i][j] > cur[j]) gt = 1;
                    if (v[i][j] < cur[j] && !gt) {
                        for (int k = j - 1; k >= -1; k--) {
                            if (k == -1) {
                                cout << "IMPOSSIBLE\n";
                                return 0;
                            }

                            if (orig[k] == '?') {
                                if (v[i][k] != '9') {
                                    v[i][k]++;
                                    break;
                                } else {
                                    v[i][k] = (k == 0) ? '1' : '0';
                                }
                            }
                        }
                        gt = 1;
                    }
                } else {
                    if (j != len - 1 || gt) {
                        if (gt) {
                            v[i][j] = '0';
                        } else {
                            v[i][j] = cur[j];
                        }
                    } else {
                        if (cur[j] != '9') {
                            v[i][j] = cur[j] + 1;
                        } else {
                            v[i][j] = '0';
                            for (int k = j - 1; k >= -1; k--) {
                                if (k == -1) {
                                    cout << "IMPOSSIBLE\n";
                                    return 0;
                                }

                                if (orig[k] == '?') {
                                    if (v[i][k] != '9') {
                                        v[i][k]++;
                                        break;
                                    } else {
                                        v[i][k] = '0';
                                    }
                                }
                            }
                        }
                    }
                }
            }

            cur = v[i];
            ans.push_back(cur);
        }
    }

    for (auto x : ans) {
        cout << x << "\n";
    }

    return 0;
}

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: WRONG ANSWER

Test 6

Group: 1, 2, 3

Verdict: WRONG ANSWER

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