Lista

#include <iostream>
#include <vector>
#include <string>
 
using namespace std;
using ll = long long;
 
string fill_blanks(string s, string l)
{
	int n = s.size();
	int qs = 0;
	for (int i = 0; i < n; ++i)
		qs += s[i] == '?';
	if (qs == 0) return s;
	if (l.empty()) {
		if (s[0] == '?') s[0] = '1';
		for (int i = 1; i < n; ++i)
			if (s[i] == '?') s[i] = '0';
		return s;
	}
	if (l.size() > s.size()) return "";
	if (l.size() < s.size()) {
		if (s[0] == '?') s[0] = '1';
		for (int i = 1; i < n; ++i)
			if (s[i] == '?') s[i] = '0';
		if (stoi(s) <= stoi(l)) return "";
		return s;
	}
	int nines = 0;
	for (int i = 0; i < n; ++i)
		nines += l[i] == '9';
	if (nines == n) return "";
	if (nines == n-1 && l[0] != '9') {
		if (s[0] == '?')
			s[0] = l[0] + 1;
		else if (s[0] <= l[0])
			return "";
	}
	vector<int> b(n);
	for (int i = 0; i < n; ++i) {
		if (s[i] == l[i] || s[i] == '?')
			b[i] = 0;
		else
			b[i] = (s[i]-l[i])/abs(s[i]-l[i]);
	}
	vector<int> qi;
	for (int i = 0; i < n; ++i) {
		if (s[i] == '?')
			qi.push_back(i);
	}
	int le = 0, gr = 0;
	while (le <= n && b[le] != -1) ++le;
	while (gr <= n && b[gr] != 1) ++gr;
	if (gr < le) {
		for (int i : qi) {
			if (i < gr) s[i] = l[i];
			else s[i] = '0';
		}
	} else if (le < gr) {
		int ti = -1;
		for (int i : qi)
			if (i < le && l[i] != '9') ti = i;
		if (ti == -1) return "";
		for (int i : qi) {
			if (i < ti) s[i] = l[i];
			else if (i == ti) s[i] = l[i]+1;
			else s[i] = '0';
		}
	} else { // only question marks
		s = to_string(stoi(l)+1);
	}
	if (stoi(s) <= stoi(l)) return "";
	return s;
//	int qs = 0;
//	for (int i = 0; i < n; ++i)
//		qs += s[i] == '?';
//	bool g = 0;
//	for (int i = 0; i < n; ++i) {
//		if (s[i] != '?') {
//			g |= s[i] > l[i];
//			continue;
//		}
//		s[i] = §		
//		if (qs == 1) {
//			if (g) continue;
//		}
//		--qs;
//	}
}
 
int main()
{
	//ios_base::sync_with_stdio(false);
	//cin.tie(nullptr);
	int n;
	cin >> n;
	vector<string> v(n);
	string l;
	for (int i = 0; i < n; ++i) {
		string s;
		cin >> s;
		s = fill_blanks(s, l);
		if (s.empty()) {
			cout << "IMPOSSIBLE" << endl;
			return 0;
		}
		v[i] = s;
		l = s;
	}
	for (string s : v)
		cout << s << endl;
}

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: 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