Package g1801_1900.s1865_finding_pairs_with_a_certain_sum

Class FindSumPairs

java.lang.Object
g1801_1900.s1865_finding_pairs_with_a_certain_sum.FindSumPairs
public class FindSumPairs extends Object
1865 - Finding Pairs With a Certain Sum\. Medium You are given two integer arrays `nums1` and `nums2`. You are tasked to implement a data structure that supports queries of two types: 1. **Add** a positive integer to an element of a given index in the array `nums2`. 2. **Count** the number of pairs `(i, j)` such that `nums1[i] + nums2[j]` equals a given value (`0 <= i < nums1.length` and `0 <= j < nums2.length`). Implement the `FindSumPairs` class: * `FindSumPairs(int[] nums1, int[] nums2)` Initializes the `FindSumPairs` object with two integer arrays `nums1` and `nums2`. * `void add(int index, int val)` Adds `val` to `nums2[index]`, i.e., apply `nums2[index] += val`. * `int count(int tot)` Returns the number of pairs `(i, j)` such that `nums1[i] + nums2[j] == tot`. **Example 1:** **Input** ["FindSumPairs", "count", "add", "count", "count", "add", "add", "count"] [[[1, 1, 2, 2, 2, 3], [1, 4, 5, 2, 5, 4]], [7], [3, 2], [8], [4], [0, 1], [1, 1], [7]] **Output:** [null, 8, null, 2, 1, null, null, 11] **Explanation:** FindSumPairs findSumPairs = new FindSumPairs([1, 1, 2, 2, 2, 3], [1, 4, 5, 2, 5, 4]); findSumPairs.count(7); // return 8; pairs (2,2), (3,2), (4,2), (2,4), (3,4), (4,4) make 2 + 5 and pairs (5,1), (5,5) make 3 + 4 findSumPairs.add(3, 2); // now nums2 = [1,4,5, **4**`,5,4`] findSumPairs.count(8); // return 2; pairs (5,2), (5,4) make 3 + 5 findSumPairs.count(4); // return 1; pair (5,0) makes 3 + 1 findSumPairs.add(0, 1); // now nums2 = [**`2` ** ,4,5,4`,5,4`] findSumPairs.add(1, 1); // now nums2 = [`2`, **5** ,5,4`,5,4`] findSumPairs.count(7); // return 11; pairs (2,1), (2,2), (2,4), (3,1), (3,2), (3,4), (4,1), (4,2), (4,4) make 2 + 5 and pairs (5,3), (5,5) make 3 + 4 **Constraints:** * `1 <= nums1.length <= 1000` * 1 <= nums2.length <= 105 * 1 <= nums1[i] <= 109 * 1 <= nums2[i] <= 105 * `0 <= index < nums2.length` * 1 <= val <= 105 * 1 <= tot <= 109 * At most `1000` calls are made to `add` and `count` **each**.

  • Constructor Details

    • FindSumPairs

      public FindSumPairs(int[] nums1, int[] nums2)

  • Method Details

    • add

      public void add(int index, int val)

    • count

      public int count(int tot)