Leetcode Problem 454. 4Sum II

454. 4Sum II

Leetcode Solutions

Approach: Hashmap

  1. Initialize a hashmap m to store the frequency of sums of pairs from nums1 and nums2.
  2. Iterate over all elements a in nums1 and b in nums2, and add the sum a + b to the hashmap, incrementing the count if the sum already exists.
  3. Initialize a count cnt to 0 for the number of valid tuples.
  4. Iterate over all elements c in nums3 and d in nums4, and for each pair, check if the negation -(c + d) exists in the hashmap m.
  5. If it exists, add the frequency of -(c + d) from the hashmap to cnt.
  6. Return the count cnt.
UML Thumbnail

Approach: kSum II (Generalized Solution)

Ask Question

Programming Language
image/screenshot of info(optional)
Full Screen
Loading...

Suggested Answer

Answer
Full Screen
Copy Answer Code
Loading...