Submission #6062706

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Source Code Expand

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

int main()
{
  int n, k;
  cin >> n >> k;

  for (int i = 1; i < n; i++)
    if (i * (i - 1) / 2 + n - 1 - i == k)
    {
      cout << n - 1 << endl;
      for (int j = 1; j <= i; j++)
        cout << j << ' ' << n << endl;
      for (int j = i + 1; j < n; j++)
        cout << 1 << ' ' << j << endl;
      return 0;
    }

  cout << -1 << endl;
}

Submission Info

Judge Result