Submission #1215029

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <string>
#include <queue>
#include <map>
#include <stack>
#include <vector>
#include <algorithm>
#include <set>
#include <deque>
#include <utility>
#include <chrono>
#include <sstream>
#include <iomanip>

#define INF 1 << 30
#define MOD 1000000007;
#define PI 3.14159265358979
#define rep(i, n) for (int (i) = 0; (i) < (int)(n); (i)++)
#define reu(i, l, r) for (int (i) = (int)(l); (i) < (int)(r); (i)++)
#define D(x) cout << x << endl
#define d(x) cout << x
#define all(x) (x).begin(), (x).end()
#define pub(x) push_back(x)
#define pob() pop_back()
#define puf(x) push_front(x)
#define pof() pop_front()
#define mp(x, y) make_pair((x), (y))
#define fi first
#define se second

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef pair<int, int> pii;
typedef pair<long, long> pll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
template<typename T, typename U> inline void amin(T &x, U y) { if (y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if (x < y) x = y; }

static const int dx[] = {0, 0, 1, -1};
static const int dy[] = {-1, 1, 0, 0};

struct UF {
  vector<int> par;
  UF(int n) : par(n) { for (int i = 0; i < n; i++) par[i] = i; }
  int find(int x) { return par[x] == x ? x : par[x] = find(par[x]); }
  bool same(int x, int y) { return find(x) == find(y); }
  void unite(int x, int y) { x = find(x); y = find(y); if (x == y) return; par[x] = y; }
};

int main() { 
  int n, m;
  cin >> n >> m;
  UF uf(101010);
  rep (i, m) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    uf.unite(a, b);
  }
  
  vb flag(n);
  rep (i, n) {
    flag[uf.find(i)] = true;
  }

  int ans = 0;
  rep (i, n) if (flag[i]) ans++;

  ans--;

  D(ans);

  return 0;
}

Submission Info

Judge Result