Duration: 60 minutes.\n\n<details> \n  <summary>Question 1</summary>\n\n![image](https://assets.leetcode.com/users/sithis/image_1563096141.png)\n</details>\n\n<details> \n  <summary>Question 2</summary>\n   \n![image](https://assets.leetcode.com/users/sithis/image_1563096124.png)\n</details>\n\n<details> \n  <summary>Question 3</summary>\n   \n   ![image](https://assets.leetcode.com/users/sithis/image_1563096188.png)\n</details>

Duration: 60 minutes.\n\n \n  Question 1\n\n\n\n\n \n  Question 2\n   \n\n\n\n \n  Question 3\n   \n   \n