Finding Pairs With a Certain Sum LeetCode solution in Java

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class FindSumPairs {
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  private int[] nums1;
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  private int[] nums2;
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  Map<Integer, Integer> map = new HashMap<>();
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  public FindSumPairs(int[] nums1, int[] nums2) {
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    this.nums1 = nums1;
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    this.nums2 = nums2;
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    for (int number : nums2) {
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      map.put(number, map.getOrDefault(number, 0) + 1);
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    }
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  }
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  public void add(int index, int val) {
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    map.put(nums2[index], map.get(nums2[index]) - 1);
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    nums2[index] += val;
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    map.put(nums2[index], map.getOrDefault(nums2[index], 0) + 1);
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  }
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  public int count(int tot) {
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    int result = 0;
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    for (int number : nums1) {
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      if (map.containsKey(tot - number)) {
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        result += map.get(tot - number);
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      }
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    }
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    return result;
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  }
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}
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/**
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 * Your FindSumPairs object will be instantiated and called as such: FindSumPairs obj = new
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 * FindSumPairs(nums1, nums2); obj.add(index,val); int param_2 = obj.count(tot);
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 */