Building Teams

input/code.cpp: In function 'int main(int, char**)':
input/code.cpp:31:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     while (i < f.size()) {
      |            ~~^~~~~~~~~~
input/code.cpp:61:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for (int i=1; i<result.size(); i++) {
      |                   ~^~~~~~~~~~~~~~

#include <iostream>
#include <vector>
#include <algorithm>
#include <format>


int main(int argc, char **argv) {

    int n, m;
    std::cin >> n >> m;

    std::vector<std::vector<int>> f;

    std::vector<int> result(n + 1, 0);

    for (int x=0; x<m; x++) {
        int f1, f2;
        std::cin >> f1 >> f2;
        if (f1 < f2) {
            f.push_back({f1, f2});
        } else {
            f.push_back({f2, f1});
        }
    }

    std::sort(f.begin(), f.end());
    //std::cout << std::format("{}", f) << std::endl;

    int i = 0;

    while (i < f.size()) {
        int insert_a = f[i][0];
        int insert_b = f[i][1];

        //std::cout << "insert_a: " << insert_a << " insert_b: " << insert_b << std::endl;

        if (result[insert_a] == 0 && result[insert_b] == 0) {
            result[insert_a] = 1;
            result[insert_b] = 2;
        } else if (result[insert_a] != 0 && result[insert_b] != 0) {
            std::cout << "IMPOSSIBLE" << std::endl;
            return 0;
        } else if (result[insert_a] != 0) {
            if (result[insert_a] == 1) {
                result[insert_b] = 2;
            } else {
                result[insert_b] = 1;
            }
        } else if (result[insert_b] != 0) {
            if (result[insert_b] == 1) {
                result[insert_a] = 2;
            } else {
                result[insert_a] = 1;
            }
        }
        
        i++;
    }


    for (int i=1; i<result.size(); i++) {
        std::cout << result[i];
    }
    std::cout << std::endl;
    

    return 0;

}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED