Intersection Count

L2 Easy Arrays & Hashing

Concept

Set intersection returns the values present in both collections at once — a one-line way to answer "what do these share?"

Return how many distinct integers appear in both a and b. A shared value is counted once, even if repeated.

Examples

▸ a = [1, 2, 3], b = [2, 3, 4]

→ 2

▸ a = [1, 2], b = [3, 4]

→ 0

▸ a = [], b = [1]

→ 0

Progressive Hints

Hint 1 · Nudge

A shared value only needs to be found once, even if it shows up many times.

Hint 2 · Plan

Turn each array into a set, then compute their intersection, the values present in both. The answer is the size of that intersection.

Hint 3 · Approach

setA = set of all of a's values; setB = set of all of b's values. Return the size of the overlap between them.

Output

// Run your code to see the output here.