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 java.lang.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 Summary

    Constructors
    Constructor
    Description
    FindSumPairs(int[] nums1, int[] nums2)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(int index, int val)
     
    int
    count(int tot)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • 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)