532. K-diff Pairs in an Array

Posted 2022-08-03 wx62ea2466cca9a

Given an array of integers and an integer k, you need to find the number of unique k-diff pairs in the array. Here a k-diff pair is defined as an integer pair (i, j), where i and j are both numbers in the array and their absolute difference is k.

Example 1:

Input: [3, 1, 4, 1, 5], k = 2
Output: 2
Explanation: There are two 2-diff pairs in the array, (1, 3) and (3, 5).
Although we have two 1s in the input, we should only return the number of

Example 2:

Input:[1, 2, 3, 4, 5], k = 1
Output: 4
Explanation: There are four 1-diff pairs in the array, (1, 2), (2, 3), (3, 4) and (4, 5).

Example 3:

Input: [1, 3, 1, 5, 4], k = 0
Output: 1
Explanation: There is one 0-diff pair in the array, (1, 1).

Note:
The pairs (i, j) and (j, i) count as the same pair.
The length of the array won’t exceed 10,000.
All the integers in the given input belong to the range: [-1e7, 1e7].

public class Solution 
     public  int findPairs(int[] nums, int k) 
        if(k<0 || nums.length<=1)
            return 0;
        

        Arrays.sort(nums);
        int count = 0;
        int left = 0;
        int right = 1;

        while(right<nums.length)
            int firNum = nums[left];
            int secNum = nums[right];
            if(secNum-firNum<k)
                right++;
            else if(secNum - firNum>k)
                left++;
            else
                count++;
                while(left<nums.length && nums[left]==firNum)
                    left++;
                
                while(right<nums.length && nums[right]==secNum)
                    right++;
                

            
            if(right==left)
                right++;
            
        
        return count;