Can you visit all rooms and score parentheses?

Problem 1: Visit all locked rooms with keys

There are n rooms labeled 0..n-1. All rooms are locked except room 0.

• When you enter room i , you find a set of keys rooms[i] .
• Each key is an integer k that unlocks room k .
• You may collect and carry all keys you find.

Task: Given rooms: List[List[int]], return true if you can eventually visit every room starting from room 0, otherwise return false.

Input/Output

• Input: rooms , where rooms[i] is the list of keys in room i
• Output: boolean

Constraints (typical):

• 1 <= n <= 10^4
• 0 <= rooms[i].length <= 10^4
• Keys are in range 0..n-1 (may include duplicates)

Problem 2: Compute the score of a balanced parentheses string

You are given a balanced parentheses string s consisting only of '(' and ')'.

Define the score recursively:

1. "()" has score 1
2. Concatenation: if A and B are balanced, then score(A + B) = score(A) + score(B)
3. Nesting: if A is balanced, then score("(" + A + ")") = 2 * score(A)

Task: Return score(s).

Input/Output

• Input: balanced string s
• Output: integer score

Constraints (typical):

• 1 <= s.length <= 10^5
• s is guaranteed balanced