Language: C++

#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <cstring>
#include <climits>
#include <iomanip>
#include <bitset>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <list>
#include <map>

using namespace std;

const long long inf = (int) 1e18;
const int N = 100005;

long long dp[N];
vector <int> adj[N];

int dfs(int u) {
  if (dp[u] != -1) return dp[u];
  long long ans = 0;
  bool done = 0;
  for (int v : adj[u]) {
    ans = max(ans, 1 + dfs(v));
    done = 1;
  }
  if (!done) return 1;
  return dp[u] = ans;
}

int main() {
  memset(dp, -1, sizeof dp);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    adj[x].push_back(y);
  }
  for (int i = 1; i <= n; i++) {
    dfs(i);
  }
  cout << max(0, *max_element(dp, dp + n) - 1) << endl;
  return 0;
}


Compiler output:
a.cc: In function 'int dfs(int)':
a.cc:33:14: error: no matching function for call to 'max(long long int&, int)'
   33 |     ans = max(ans, 1 + dfs(v));
      |           ~~~^~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 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:33:14: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   33 |     ans = max(ans, 1 + dfs(v));
      |           ~~~^~~~~~~~~~~~~~~~~
/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,
                 from a.cc:11:
/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:33:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   33 |     ans = max(ans, 1 + dfs(v));
      |           ~~~^~~~~~~~~~~~~~~~~
a.cc: In function 'int main()':
a.cc:52:14: error: no matching function for call to 'max(int, long long int)'
   52 |   cout << max(0, *max_element(dp, dp + n) - 1) << endl;
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:52:14: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   52 |   cout << max(0, *max_element(dp, dp + n) - 1) << endl;
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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
/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:52:14: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   52 |   cout << max(0, *max_element(dp, dp + n) - 1) << endl;
      |           ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~