Given an integer array nums and an integer k, return the number of pairs (i, j) where i < j such that |nums[i] - nums[j]| == k.
The value of |x| is defined as:
x if x >= 0.-x if x < 0.
Example 1:
Input: nums = [1,2,2,1], k = 1 Output: 4 Explanation: The pairs with an absolute difference of 1 are: - [1,2,2,1] - [1,2,2,1] - [1,2,2,1] - [1,2,2,1]
Example 2:
Input: nums = [1,3], k = 3 Output: 0 Explanation: There are no pairs with an absolute difference of 3.
Example 3:
Input: nums = [3,2,1,5,4], k = 2 Output: 3 Explanation: The pairs with an absolute difference of 2 are: - [3,2,1,5,4] - [3,2,1,5,4] - [3,2,1,5,4]
Constraints:
1 <= nums.length <= 2001 <= nums[i] <= 1001 <= k <= 99struct Solution;
impl Solution {
fn count_k_difference(nums: Vec<i32>, k: i32) -> i32 {
let n = nums.len();
let mut res = 0;
for i in 0..n {
for j in i + 1..n {
if (nums[j] - nums[i]).abs() == k {
res += 1;
}
}
}
res
}
}
#[test]
fn test() {
let nums = vec![1, 2, 2, 1];
let k = 1;
let res = 4;
assert_eq!(Solution::count_k_difference(nums, k), res);
let nums = vec![1, 3];
let k = 3;
let res = 0;
assert_eq!(Solution::count_k_difference(nums, k), res);
let nums = vec![3, 2, 1, 5, 4];
let k = 2;
let res = 3;
assert_eq!(Solution::count_k_difference(nums, k), res);
}