Create 1865-finding-pairs-with-a-certain-sum.js

Author: everthis

1865-finding-pairs-with-a-certain-sum.js

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+
+/**
+ * @param {number[]} nums1
+ * @param {number[]} nums2
+ */
+const FindSumPairs = function(nums1, nums2) {
+  this.nums1 = nums1
+  this.nums2 = nums2
+  const m = nums1.length, n = nums2.length
+  this.mp = {}
+  for(let x of nums2) {
+    if(this.mp[x] == null) this.mp[x] = 0
+    this.mp[x]++
+  }
+};
+
+/** 
+ * @param {number} index 
+ * @param {number} val
+ * @return {void}
+ */
+FindSumPairs.prototype.add = function(index, val) {
+  if(val !== 0) {
+    if(!(--this.mp[this.nums2[index]])) delete this.mp[this.nums2[index]]    
+  }
+  this.nums2[index] += val
+  if(this.mp[this.nums2[index]] == null) this.mp[this.nums2[index]] = 0
+  if(val !== 0)this.mp[this.nums2[index]]++
+};
+
+/** 
+ * @param {number} tot
+ * @return {number}
+ */
+FindSumPairs.prototype.count = function(tot) {
+  let ans = 0;
+  for (let x of this.nums1) {
+    let res = tot - x;
+    if (!this.mp[res]) continue;
+    ans += this.mp[res];
+  }
+  return ans;
+};
+
+/** 
+ * Your FindSumPairs object will be instantiated and called as such:
+ * var obj = new FindSumPairs(nums1, nums2)
+ * obj.add(index,val)
+ * var param_2 = obj.count(tot)
+ */