![image](https://assets.leetcode.com/users/images/9d57a52c-c90d-4e85-8f80-87c4d34cc98e_1630224050.2764347.jpeg)\n![image](https://assets.leetcode.com/users/images/02712a00-a53c-48e1-accb-61609bbe5a02_1630224050.057338.jpeg)\n![image](https://assets.leetcode.com/users/images/60d58a4d-77f0-4810-b3e8-221379577ad7_1630224050.0499876.jpeg)\n\nHi, urgent! Does anyone know how to approach these problems, thanks?

\n\n\n\nHi, urgent! Does anyone know how to approach these problems, thanks?