Create 1570-dot-product-of-two-sparse-vectors.js

Author: everthis

1570-dot-product-of-two-sparse-vectors.js

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+/**
+ * @param {number[]} nums
+ * @return {SparseVector}
+ */
+const SparseVector = function(nums) {
+  this.seen = {}
+  nums.forEach((e, i) => {
+    if(e !== 0) this.seen[i] = e
+  })
+};
+
+// Return the dotProduct of two sparse vectors
+/**
+ * @param {SparseVector} vec
+ * @return {number}
+ */
+SparseVector.prototype.dotProduct = function(vec) {
+  let res = 0
+  for(let [k, v] of Object.entries(vec.seen)) {
+    if(k in this.seen) res += v * this.seen[k]
+  }
+  return res
+};
+
+// Your SparseVector object will be instantiated and called as such:
+// let v1 = new SparseVector(nums1);
+// let v2 = new SparseVector(nums2);
+// let ans = v1.dotProduct(v2);