1570. Dot Product of Two Sparse Vectors

1class SparseVector {
2		map: Map<number, number>;
3    constructor(nums: number[]) {
4			this.map = new Map();
5			nums.forEach((val, idx) => {
6				if(val !== 0) this.map.set(idx, val)
7			})
8    }
9
10	// Return the dotProduct of two sparse vectors
11    dotProduct(vec: SparseVector): number {
12			const [smaller, larger] = this.map.size < vec.map.size ? [this.map, vec] : [vec, this.map];
13			let res = 0;
14			for(const [idx, val] of smaller.entries()) {
15				res += val * (larger.get(idX) ?? 0);
16			}
17			return res;
18    }
19}
20
21/**
22 * Your SparseVector object will be instantiated and called as such:
23 * var v1 = new SparseVector(nums1)
24 * var v2 = new SparseVector(nums1)
25 * var ans = v1.dotProduct(v2)
26 */