leetcode2176: Count Equal and Divisible Pairs in an Array

[carloscn]

Description

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

[carloscn]

Analysis

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

    if nums.len() < 1 {
        return ret;
    }

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

    return ret;
}

[carloscn]

Code

https://review.gerrithub.io/c/carloscn/structstudy/+/1169571 https://github.com/carloscn/structstudy/commit/6e34aa562dfd3d9a2e754d095766d50c76bbadbf