Language: C++

#include <bits/stdc++.h>

#define ld long double
#define ll long long int
#define ull unsigned long long int

using namespace std;

int main() {


    int N,M;
    cin >> N >> M;
    vector<int> v(N);
    vector<int> p(M,0); // 県番号管理
    vector<int> y(M,0); // year


    for (int i = 0; i < M; ++i) {
        int temp ;
        cin >> temp;
        p[i] = temp - 1;
        cin >> y[i];
        v[p[i]].push_back(y[i]);
    }

    for(int i = 0; i < N; i++) {
        sort(v[i].begin(), v[i].end());
    }

    for(int i = 0; i < M; i++) {
        int ans = (p[i] + 1) * 1000000 + (int)(lower_bound(v[p[i]].begin(), v[p[i]].end(), y[i]) - v[p[i]].begin()) + 1;
        cout << setfill('0') << setw(12) << ans << endl;
    }



}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:17: error: request for member 'push_back' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)p.std::vector<int>::operator[](((std::vector<int>::size_type)i))))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   24 |         v[p[i]].push_back(y[i]);
      |                 ^~~~~~~~~
a.cc:28:19: error: request for member 'begin' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   28 |         sort(v[i].begin(), v[i].end());
      |                   ^~~~~
a.cc:28:33: error: request for member 'end' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)i))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   28 |         sort(v[i].begin(), v[i].end());
      |                                 ^~~
a.cc:32:68: error: request for member 'begin' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)p.std::vector<int>::operator[](((std::vector<int>::size_type)i))))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   32 |         int ans = (p[i] + 1) * 1000000 + (int)(lower_bound(v[p[i]].begin(), v[p[i]].end(), y[i]) - v[p[i]].begin()) + 1;
      |                                                                    ^~~~~
a.cc:32:85: error: request for member 'end' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)p.std::vector<int>::operator[](((std::vector<int>::size_type)i))))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   32 |         int ans = (p[i] + 1) * 1000000 + (int)(lower_bound(v[p[i]].begin(), v[p[i]].end(), y[i]) - v[p[i]].begin()) + 1;
      |                                                                                     ^~~
a.cc:32:108: error: request for member 'begin' in 'v.std::vector<int>::operator[](((std::vector<int>::size_type)p.std::vector<int>::operator[](((std::vector<int>::size_type)i))))', which is of non-class type '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'}
   32 |         int ans = (p[i] + 1) * 1000000 + (int)(lower_bound(v[p[i]].begin(), v[p[i]].end(), y[i]) - v[p[i]].begin()) + 1;
      |                                                                                                            ^~~~~