Submission #1462916

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Source Code Expand

#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <algorithm>
#include <deque>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <new>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
typedef int64_t i64;

int main() {
	ios_base::sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  vector<bool> x(n), y(n);
  for(; m > 0; m--) {
    int a, b;
    cin >> a >> b; a--; b--;
    if(a == 0) {
      x[b] = true;
    } else if(b == n - 1) {
      y[a] = true;
    }
  }
  for(int i = 1; i + 1 < n; i++) {
    if(x[i] && y[i]) {
      cout << "POSSIBLE" << endl;
      return 0;
    }
  }
  cout << "IMPOSSIBLE" << endl;
  return 0;
}

Submission Info

Judge Result