Language: C++

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#define REP(i,n) for(int i=0;i<n;i++)
#define REPP(i,n) for(int i=1;i<=n;i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
//const double PI = acos(-1);
//const double EPS = 1e-15;
//long long INF=(long long)1E17;
#define i_7 (long long)(1e9+7)
//#define i_7 998'244'353
long mod(long a){
    long long c=a%i_7;
    if(c>=0)return c;
    return c+i_7;
}
using namespace std;

bool prime_(int n){
  if(n==1){
    return false;
  }else if(n==2){
    return true;
  }else{
    for(int i=2;i<=sqrt(n);i++){
      if(n%i==0){
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b){
  if(a<b){
    swap(a,b);
  }
  if(a%b==0){
    return b;
  }else{
    return gcd_(b,a%b);
  }
}
 
long long lcm_(long long x, long long y){
  return (x/gcd_(x,y))*y;
}

vector<int> G[100'010];
int maxdeg = 0;
map<pair<int, int>, int> color;
void dfs(int v, int p){
  //bool used[k] = {};
  int ban_c =  color[make_pair(p,v)];
  int now = 1;
  for(int nv:G[v]){
    if(nv == p){
      //used[color[make_pair(p,v)] - 1] = true;
      continue;
    }else{
      if(now == ban_c){
        now++;
      }
      color[make_pair(nv,v)] = color[make_pair(v,nv)] = now;
      now++;
      dfs(nv, v);//ちょっと微妙
    }
  }
  return;
}

int main(){
  
  int n;
  cin>>n;
  int a[n-1],b[n-1];
  REP(i,n-1){
    cin>>a[i]>>b[i];
    a[i]--;b[i]--;
    G[a[i]].push_back(b[i]);
    G[b[i]].push_back(a[i]);
  }
  REP(i,n){
    maxdeg = max(maxdeg, G[i].size());
  }
  dfs(0, -1);
  cout<<maxdeg<<endl;
  REP(i,n-1){
    int c = map[make_pair(a[i],b[i])];
    cout<<c<<endl;
  }
  return 0; 
}


Compiler output:
a.cc: In function 'int main()':
a.cc:86:17: error: no matching function for call to 'max(int&, std::vector<int>::size_type)'
   86 |     maxdeg = max(maxdeg, 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:86:17: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::vector<int>::size_type' {aka 'long unsigned int'})
   86 |     maxdeg = max(maxdeg, 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:86:17: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   86 |     maxdeg = max(maxdeg, G[i].size());
      |              ~~~^~~~~~~~~~~~~~~~~~~~~
a.cc:91:16: error: missing template arguments before '[' token
   91 |     int c = map[make_pair(a[i],b[i])];
      |                ^