Problem Brief

Find Number of Valid Pairs

INTERNOA

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Imagine you have two long lists of numbers, let’s call them a and b, and they are exactly the same length. Your goal is to find special pairs of positions, (i, j), where i is smaller than j, and something interesting happens between the numbers at these positions. For each pair, you’re looking for this magical balance: When you take the number from list a at position i and subtract the number from list b at position j, it should be equal to what you get when you take the number from list a at position j and subtract the number from list b at position i. Your task is to figure out how many such special pairs exist in these two lists.

1Example 1

Input

a = [2, -2, 5, 3], b = [1, 5, -1, 1]

Output

Explanation

see the problem source section below for the original explanation ;)

Constraints

Limits and guarantees your solution can rely on.

🍇🍇

Draft autosaves locally

public int validPairs(int[] a, int[] b) {
  // write your code here
}

Input

[2, -2, 5, 3]

[1, 5, -1, 1]

Output