Language: C++

// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define range(i,a,b) ((a)<=(i) && (i)<(b))
#define debug(x) cout << #x << " = " << (x) << endl;
#define fs first
#define sc second
#define pb push_back
#define eb emplace_back

typedef long long ll;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> T;
typedef vector<ll> vec;
typedef vector<P> pvec;
typedef vector<vector<ll>> vvec;
typedef vector<vector<P>> pvvec;
typedef priority_queue<ll> PQI;
typedef priority_queue<P> PQP;
typedef priority_queue<ll,vector<ll>,greater<ll>> PQIG;
typedef priority_queue<P,vector<P>,greater<P>> PQPG;

const vector<int> dx = {0, -1, 0, 1, 1, 1, -1, -1};
const vector<int> dy = {1, 0, -1, 0, 1, -1, 1, -1};
constexpr int MOD = (1000000007);
// const int MOD = (998244353);
// const int INF = (1 << 30); // 1073741824
const int INF = (1LL << 60); // 1152921504606846976
const double EPS = (1 >> 30);

template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return 1;} return 0;}
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return 1;} return 0;}
template<class T> inline T ceil(T a, T b) {return T((a + b - 1)/b);}
template< typename T1, typename T2 > istream &operator>>(istream &is, pair< T1, T2 > &p) { is >> p.first >> p.second; return is; }

int nmax=200000; // 2*(10^5)
vvec g(nmax);

struct UnionFind {
  private:
  vector<int> child,tree;
  vector<vector<int>> list;

public:
  UnionFind(int v) {
    tree.resize(v);
    list.resize(v);
    REP(i,v) tree[i] = i, list[i].push_back(i);
  }

  int root(int i){
    if(i == tree[i]){
      REP(j,child.size()) tree[child[j]] = i;
      child.clear(); 
      return i;
    }
    else{
      child.push_back(i);
      return i = root(tree[i]);
    }
  }

  int size(int i){
    return list[root(i)].size();
  }

  vector<int> nodes(int no){
    return list[root(no)];
  }

  bool unit(int x, int y){
    x = root(x);
    y = root(y);
    if(x==y) return false;
    if(list[x].size() < list[y].size()) swap(x,y);
    for(int no:list[y]) list[x].emplace_back(no);
    tree[y] = x;
    return true;
  }

  bool isUnit(int x, int y){
    return root(x) == root(y);
  }
};

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);
    //---------------------------------------------
    
    int n,m;
    cin>>n>>m;
    vector<int> a(n);
    rep(i,n) cin >> a[i];
    pvec cost(n);
    rep(i,n){

    }
    UnionFind uf(n);
    rep(i,m){
        int x,y;
        cin>>x>>y;
        uf.unit(x,y);
    }
    vector<PQPG> G(n);
    rep(i,n){
        G[uf.root(i)].push(P(a[i],i));
    }
    int ans=0;
    
    int ki=0;
    rep(i,n){
        if(G[i].size()!=0){
            ans+=G[i].top().fs;
            a[G[i].top().sc]=0;
            ki++;
            debug(G[i].top().sc);
            debug(G[i].top().fs);
        }
    }
    int cnt=ki;
    ki--;
    ki*=2;
    sort(all(a));
    rep(i,n){
        if(a[i]==0) continue;
        if(ki==cnt) break;
        ans+=a[i];
        cnt++;
    }
    if(n=<m+1){
        cout<<0<<endl;
        return 0;
    }
    if(ki!=cnt){
        cout<<"Impossible"<<endl;
    }
    else{
        cout<<ans<<endl;
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:139:10: error: expected primary-expression before '<' token
  139 |     if(n=<m+1){
      |          ^