title: Time Complexity of input a data
body: <p>There is any cost of taking 2d array as input ?</p>
  <pre><code>
  for(int i = 0; i &lt; n; i++) {
     for(int j = 0; j &lt; n; j++) {
       cin &gt;&gt; a[i][j];
     }
  }
  </code></pre>
  <p>Is it O(n^2) time complexity  or O(1)?</p>