Language: C++

#include <bits/stdc++.h>

#define rep(i, n) for(int i = 0; i<(n); i++)
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef long long ll;

const int MOD = 1000000007;

struct Edge {
    int to, id
};

vector<vector<Edge>> g;
vector<int> ans;

void dfs(int v, int c = -1, int p = -1) {
    int k = 1;
    rep(i, g[v].size()) {
        int u = g[v][i].to, ei = g[v][i].id;
        if (u == p) continue; // 親との辺の場合
        if (k == c) k++; // 親で使用した色の場合
        ans[ei] = k;
        k++;
        dfs(u, ans[ei], v);
    }
}

int main() {
    int N;
    cin >> N;
    g.resize(N);
    ans = vector<int>(N - 1);
    rep(i, N - 1) {
        int a, b;
        cin >> a >> b;
        --a;
        --b;
        g[a].push_back({b, i})
        g[b].push_back({a, i})
    }

    dfs(0);
    int mx = 0;
    rep(i, N) mx = max(mx, g[i].size());

    cout << mx << endl;
    rep(i, N - 1) {
        cout << ans[i] << endl;
    }
}


Compiler output:
a.cc:12:13: error: expected ';' at end of member declaration
   12 |     int to, id
      |             ^~
      |               ;
a.cc: In function 'int main()':
a.cc:40:31: error: expected ';' before 'g'
   40 |         g[a].push_back({b, i})
      |                               ^
      |                               ;
   41 |         g[b].push_back({a, i})
      |         ~                      
a.cc:41:30: error: expected primary-expression before ')' token
   41 |         g[b].push_back({a, i})
      |                              ^
a.cc:46:23: error: no matching function for call to 'max(int&, std::vector<Edge>::size_type)'
   46 |     rep(i, N) mx = max(mx, g[i].size());
      |                    ~~~^~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:46:23: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::vector<Edge>::size_type' {aka 'long unsigned int'})
   46 |     rep(i, N) mx = max(mx, g[i].size());
      |                    ~~~^~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:46:23: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   46 |     rep(i, N) mx = max(mx, g[i].size());
      |                    ~~~^~~~~~~~~~~~~~~~~