Language: C++

#include <bits/stdc++.h>

#define rep(i,n) for(long long int (i)=0;(i)<(int)(n);(i)++)
#define rrep(i,a,b) for(long long int i=(a);i<(b);i++)
#define rrrep(i,a,b) for(long long int i=(a);i>=(b);i--)
#define all(v) (v).begin(), (v).end()
#define pb(q) push_back(q)
#define Abs(a,b) max(a,b)-min(a,b)
#define YES(condition) if(condition){cout << "YES" << endl;}else{cout << "NO" << endl;}
#define Yes(condition) if(condition){cout << "Yes" << endl;}else{cout << "No" << endl;}
#define Cout(x) cout<<(x)<<endl
#define POSSIBLE(condition) if(condition){cout << "POSSIBLE" << endl;}else{cout << "IMPOSSIBLE" << endl;}
#define Possible(condition) if(condition){cout << "Possible" << endl;}else{cout << "Impossible" << endl;}
#define possible(condition) if(condition){cout << "possible" << endl;}else{cout << "impossible" << endl;}
#define Size(n) (n).size()

typedef long long ll;


using namespace std;

const int INF = 1e9,MOD = 1e9 + 7,ohara=1e6;
const ll LINF = 1e18;

/*---------------------------------------------------------------
long long int kaizyo(long long int hh){
    cmp=1;
    while(hh>1){
        cmp=(cmp*hh)%MOD;
        hh--;
    }
    return cmp;
}
long long int ruizyo(long long int aa, long long int bb){
    if(aa==0){
        return 1;
    }
    else if(aa%2==0){
        long long int tt=ruizyo(aa/2,bb);
        return (tt*tt)%MOD;
    }
    else{
        return (ruizyo(aa-1,bb)*bb)%MOD;
    }
}フェルマ－のア
---------------------------------------------------------------

while(x!=0){
            sum+=x%10;
          / x/=10;
        }
        各桁の和
---------------------------------------------------------------

pair<int,int> p[100000];
cin >> tmp;
p[i]=make_pair(tmp,i);
cout << p[i].second+1 << endl;//ペアの右側つまりiを出力

---------------------------------------------------------------

bool f[100001];//1000000以下の素数を調べよう！
rrep(i,2,100001){
       f[i]=false;
    }
rrep(i,2,100001){
        if(!f[i]){
            for(int j=i+i;j<=100000;j+=i){
                f[j]=true;
            }
        }
    }
    for(int i=3;i<=100000;i+=2){
        if(!f[i]){
            c[i]++;
        }
    }

---------------------------------------------------------------

long long gcd(long long aaa,long long bbb){
    if(bbb==0){
        return aaa;
    }
    return gcd(bbb,aaa%bbb);
}
 
long long lcm(long long aaa,long long bbb){
    long long g = gcd(aaa,bbb);
    return aaa/g * bbb;
}左から最大公約数と最小公倍数


---------------------------------------------------------------

long long int prime_cnt[10000];
       for(int i=2;i*i<=n;i++){
           while(n%i==0){
               n/=i;
               prime_cnt[i]+=1;
           }
           if(n>1){
               prime_cnt[n]+=1;
               break;
           }
      }ある数nを素因数分解しましょう

---------------------------------------------------------------
debug:
cout<<"i: "<<i<<" j: "<<j<<" cnt: "<<cnt<<"\n";

---------------------------------------------------------------*/

long long int n,cnt=0,ans=0,a,b,c,d,cmp,cmpp,m,h,w,x,y,sum=0,pos,par[ohara],ran[ohara];
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};
string alph("abcdefghijklmnopqrstuvwxyz"),s;
bool fl=true;
struct edge{int to,cost;};

//-------------------------↓↓↓↓↓↓------------------------

void init(int nn) {
	for (int i=0; i<nn; i++) {
		par[i] = i;
		ran[i] = 0;
	}
}//初期化

ll root(ll xx){
    if(par[xx]==xx){
        return xx;
    }
    else{
        return par[xx]=root(par[xx]);
    }
}
//木の根を求めている。
 
bool same(ll xx,ll yy){
    return root(xx)==root(yy);
}
//同じ集合？？
 
void unite(ll xx,ll yy){
    xx=root(xx);
    yy=root(yy);
    if(xx==yy)return;
    
    if(ran[xx]<ran[yy]){
        par[xx]=yy;
    }
    else{
        par[yy]=xx;
        if(ran[xx]==ran[yy])ran[xx]++;
    }
}
//xとyの属する集合を併合
 
int main(void){
       cin.tie(0);
    ios::sync_with_stdio(false);
 
       cin >> n >> m;
       rep(i,n){
           cin>>a;
           if(a==i+1)ans++;
       }
     init(n);
      rep(i,m){
          cin >> a >> b;
          unite(a,b);
      }
      set<int> st;
      rrep(i,1,n+1){
          st.insert(root(i));
      }
      if(Size(st)==1)Cout(n);
      else{
      Cout(max(n-st.size(),ans));
      }
return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:180:15: error: no matching function for call to 'max(long long unsigned int, long long int&)'
  180 |       Cout(max(n-st.size(),ans));
      |            ~~~^~~~~~~~~~~~~~~~~
a.cc:11:24: note: in definition of macro 'Cout'
   11 | #define Cout(x) cout<<(x)<<endl
      |                        ^
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:180:15: note:   deduced conflicting types for parameter 'const _Tp' ('long long unsigned int' and 'long long int')
  180 |       Cout(max(n-st.size(),ans));
      |            ~~~^~~~~~~~~~~~~~~~~
a.cc:11:24: note: in definition of macro 'Cout'
   11 | #define Cout(x) cout<<(x)<<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
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:180:15: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long unsigned int'
  180 |       Cout(max(n-st.size(),ans));
      |            ~~~^~~~~~~~~~~~~~~~~
a.cc:11:24: note: in definition of macro 'Cout'
   11 | #define Cout(x) cout<<(x)<<endl
      |                        ^