leetcode/kth_smallest_pair.py at master · adwaymalhotra/leetcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
class Solution:
    def smallestDistancePair(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: int
        """
        def countPairs(ns, ans):
            c = 0
            for i in range(N):
                ind = bisect.bisect_right(nums, nums[i]+ans)
                if ind == N:
                    c += sum([x for x in range(1,N-i)])
                    break
                else:
                    c += ind-i-1
            return c

        N = len(nums)
        if N<2: return 0
        nums.sort()

        lo = 0
        hi = nums[-1]-nums[0]

        while lo<=hi:
            ans = (lo+hi)//2
            # counting number of pairs with distance <= ans
            if countPairs(nums, ans)<k:
                lo = ans+1
            else:
                hi = ans-1
        return lo