Language: C++

#include<bits/stdc++.h>

using namespace std;

struct Edge{
    int to,id;
};

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

void dfs(int v,int p_color=-1,int parent=-1);

int main(){
    int n;
    cin >> n;
    g.resize(n);
    for(int i=0;i<n;i++){
        int a,b;
        cin >> a >> b;
        a--;
        b--;
        g[a].push_back((Edge){b,i});
        g[b].push_back((Edge){a,i});
    }
    dfs(0);
    int m=0;
    for(int i=0;i<n;i++){
        m=max(m,g[i].size());
    }
    cout << m << endl;
    for(int i=0;i<n-1;i++){
        cout << ans[i] << endl;
    }

    return 0;
}

void dfs(int v,int p_color=-1,int parent=-1){
    int k=1;
    for(i=0;i<g[v].size()){
        int u=g[v][i].to;
        int edge_id=g[v][i].id;
        if(u==parent) continue;
        if(k==p_color) k++;
        ans[edge_id]=k;
        k++;
        dfs(u,ans[edge_id],v);
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:29:14: error: no matching function for call to 'max(int&, std::vector<Edge>::size_type)'
   29 |         m=max(m,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:29:14: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::vector<Edge>::size_type' {aka 'long unsigned int'})
   29 |         m=max(m,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:29:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   29 |         m=max(m,g[i].size());
      |           ~~~^~~~~~~~~~~~~~~
a.cc: At global scope:
a.cc:39:6: error: default argument given for parameter 2 of 'void dfs(int, int, int)' [-fpermissive]
   39 | void dfs(int v,int p_color=-1,int parent=-1){
      |      ^~~
a.cc:12:6: note: previous specification in 'void dfs(int, int, int)' here
   12 | void dfs(int v,int p_color=-1,int parent=-1);
      |      ^~~
a.cc:39:6: error: default argument given for parameter 3 of 'void dfs(int, int, int)' [-fpermissive]
   39 | void dfs(int v,int p_color=-1,int parent=-1){
      |      ^~~
a.cc:12:6: note: previous specification in 'void dfs(int, int, int)' here
   12 | void dfs(int v,int p_color=-1,int parent=-1);
      |      ^~~
a.cc: In function 'void dfs(int, int, int)':
a.cc:41:9: error: 'i' was not declared in this scope
   41 |     for(i=0;i<g[v].size()){
      |         ^
a.cc:41:26: error: expected ';' before ')' token
   41 |     for(i=0;i<g[v].size()){
      |                          ^
      |                          ;