- Difficulty: Medium
- Tags: LeetCode, Medium, Design, Array, Hash Table, Two Pointers, leetcode-1570, O(n), 🔒
Problem
Given two sparse vectors, compute their dot product.
Implement class SparseVector
:
SparseVector(nums)
 Initializes the object with the vectornums
dotProduct(vec)
 Compute the dot product between the instance of SparseVector andvec
A sparse vector is a vector that has mostly zero values, you should store the sparse vector efficiently and compute the dot product between two SparseVector.
Follow up:Â What if only one of the vectors is sparse?
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Example 1:
Input: nums1 = [1,0,0,2,3], nums2 = [0,3,0,4,0] Output: 8 Explanation: v1 = SparseVector(nums1) , v2 = SparseVector(nums2) v1.dotProduct(v2) = 1*0 + 0*3 + 0*0 + 2*4 + 3*0 = 8
Example 2:
Input: nums1 = [0,1,0,0,0], nums2 = [0,0,0,0,2] Output: 0 Explanation: v1 = SparseVector(nums1) , v2 = SparseVector(nums2) v1.dotProduct(v2) = 0*0 + 1*0 + 0*0 + 0*0 + 0*2 = 0
Example 3:
Input: nums1 = [0,1,0,0,2,0,0], nums2 = [1,0,0,0,3,0,4] Output: 6
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Constraints:
n == nums1.length == nums2.length
1 <= n <= 10^5
0 <= nums1[i], nums2[i]Â <= 100