Submission #294748

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Source Code Expand

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

#define iota(i,n,b,s) for(int i=int(b);i!=int((b)+(s)*(n));i+=(s))
#define range(i,n,m) iota(i,(((n)>(m))?((n)-(m)+1):((m)-(n)+1)),(n),((n)>(m)?-1:1))
#define rep(i,n) iota(i,(n),0,1)

#define INF (1e9)
#define EPS (1e-9)
#define cons(a,b) (make_pair(a,b))
#define car(a) (a.first)
#define cdr(a) (a.second)
#define cadr(a) (car(cdr(a)))
#define cddr(a) (cdr(cdr(a)))
#define all(a) a.begin(), a.end()
#define trace(var) cerr<<">>> "<<#var<<" = "<<var<<endl;

#define read_int(x) int x; cin >> x;

typedef long long INTEGER;
typedef double FLOAT;

template<class S, class T>
ostream& operator<<(ostream& os, pair<S,T> p) {
  os << '(' << car(p) << ", " << cdr(p) << ')';
  return os;
}

template<class T>
ostream& operator<<(ostream& os, vector<T> v) {
  os << v[0];
  for (int i=1, len=v.size(); i<len; ++i) os << ' ' << v[i];
  return os;
}

bool visited[51];
vector<int> L;
vector<vector<int> > neigh;

void visit(int u) {
  if (visited[u]) return;
  visited[u] = true;
  for (int v : neigh[u]) {
    if (v == 0) visit(0);
  }
  for (int v : neigh[u]) {
    if (v != 0) visit(v);
  }
  L.push_back(u);
}

int main() {

  read_int(n);
  read_int(m);

  neigh.resize(n);
  rep (i, m) {
    int a, b; cin >> a >> b;
    --a; --b;
    neigh[b].push_back(a);
  }

  rep (i, n) visited[i] = false;
  rep (i, n) visit(i);

  cerr << L << endl;

  rep (i, n) {
    if (L[i] == 0) cout << (i + 1) << endl;
  }

  return 0;
}

Submission Info

Judge Result