Lista

input/code.cpp: In function 'std::string edit(std::string, std::string, std::string)':
input/code.cpp:48:55: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |                                 for (int j = i + 1; j < s.length(); j++)
      |                                                     ~~^~~~~~~~~~~~
input/code.cpp: In function 'int main()':
input/code.cpp:95:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |                 for (int j = 0; j < s.length(); j++)
      |                                 ~~^~~~~~~~~~~~

#include <iostream>
#include <string>
#include <math.h>
#include <map>
#include <algorithm>
#include <vector>
#include <fstream>
#include <set>
#include <unordered_map>
#include <queue>
#include <climits>
#include <stack>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define S second
#define F first
#define A 999999999999999999LL
#define M 1000000007
// https://cses.fi/dt/
int n;
int t;
int mypow(int a, int b) {
	if (b == 0) return 1;
	int num = 1;
	while (b--) {
		num *= a;
	}
	return num;
}
string edit(string s, string last, string org)
{
	int difference = stoi(s) - stoi(last);
	if (difference < 0) return s;
	int potentialsavings = 0;
	for (int i = s.length() - 1; i >= 0; i--)
	{
		if (org[i] != '?')
			continue;
		int limit = s[i] - '0';
		for (int k = 1; k <= limit; k++)
		{
			s[i] = to_string(limit - k)[0];
			if (k * pow(10, s.length() - i - 1) + potentialsavings > difference)
			{
				int extra = k * mypow(10, s.length() - i - 1) + potentialsavings - difference - 1;

				for (int j = i + 1; j < s.length(); j++)
				{
					if (org[j] != '?')
						continue;
					int amount = extra / mypow(10, s.length() - j - 1);
					amount = min(amount,9);
					extra -= amount * mypow(10, s.length() - j - 1);
					s[j] = to_string(amount)[0];
				}
				return s;
			}
		}
		potentialsavings += limit * pow(10, s.length() - i - 1);
	}

	return s;
}
#define N (1 << 17)
int main()
{
	cin >> n;
	vector<string> v;
	vector<string> t;
	for (int i = 0; i < n; i++)
	{
		string s; cin >> s;
		t.push_back(s);
	}
	string last = t[t.size() - 1];
	replace(last.begin(), last.end(), '?', '9');
	v.push_back(last);
	for (int i = t.size() - 2; i >= 0; i--)
	{
		string s = t[i];
		string org = s;
		if (s.length() < last.length())
		{
			replace(s.begin(), s.end(), '?', '9');
			v.push_back(s);
			last = s;
			continue;
		}
		if (s.length() > last.length())
		{
			cout << "IMPOSSIBLE";
			exit(0);
		}
		for (int j = 0; j < s.length(); j++)
		{
			if (s[j] == '?') s[j] = '9';
		}
		s = edit(s, last,org);

		if (stoi(s) < stoi(last))
		{
			v.push_back(s);
		}
		else
		{
			cout << "IMPOSSIBLE";
			exit(0);
		}
		last = s;
	}
	for (int i = v.size() - 1; i >= 0; i--)
	{
		cout << v[i] << "\n";
	}
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED

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: ACCEPTED

Test 10

Group: 3

Verdict: ACCEPTED