2176. Count Equal and Divisible Pairs in an Array

Problem Statement

Given a 0-indexed integer array nums of length n and an integer k, return the number of pairs (i, j) where 0 <= i < j < n, such that nums[i] == nums[j] and (i * j) is divisible by k.

Example 1:

Input: nums = [3,1,2,2,2,1,3], k = 2
Output: 4
Explanation:
There are 4 pairs that meet all the requirements:
- nums[0] == nums[6], and 0 * 6 == 0, which is divisible by 2.
- nums[2] == nums[3], and 2 * 3 == 6, which is divisible by 2.
- nums[2] == nums[4], and 2 * 4 == 8, which is divisible by 2.
- nums[3] == nums[4], and 3 * 4 == 12, which is divisible by 2.

Example 2:

Input: nums = [1,2,3,4], k = 1
Output: 0
Explanation: Since no value in nums is repeated, there are no pairs (i,j) that meet all the requirements.

Constraints:

1 <= nums.length <= 100
1 <= nums[i], k <= 100

Click to open Hints

For every possible pair of indices (i, j) where i < j, check if it satisfies the given conditions.

Solution:

Rust

impl Solution {
    pub fn count_pairs(nums: Vec<i32>, k: i32) -> i32 {
        let mut ans = 0;

        for i in 0..nums.len() {
            for j in i + 1..nums.len() {
                if nums[i] == nums[j] && (i * j) % k as usize == 0 {
                    ans += 1;
                }
            }
        }

        ans
    }
}

2176. Count Equal and Divisible Pairs in an Array #

Problem Statement #

Solution: #

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2176. Count Equal and Divisible Pairs in an Array

Problem Statement

Solution:

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