Mock 1 — Arrays, Strings & Hashing

What does this print?

nums = [3, 1, 4, 1, 5]
seen = set()
dup = None
for x in nums:
    if x in seen:
        dup = x
        break
    seen.add(x)
print(dup)

What is the time complexity of the code above for n elements?

Group Anagrams: which key groups "eat", "tea" and "ate" together? (select all that apply)

What is the maximum subarray sum of [5, -9, 6, -2, 3]?

What does this Java snippet print?

String a = new String("hi");
String b = new String("hi");
System.out.println(a == b);

Product of Array Except Self for [1, 2, 3, 4] returns…

How many subarrays of [1, 1, 1] have sum 2?

Which approach finds the majority element (appears > n/2 times) in O(n) time and O(1) space?

What is the longest consecutive sequence length in [100, 4, 200, 1, 3, 2]?

Which is the fastest correct way to check if two lowercase strings are anagrams?