973. K Closest Points to Origin

[tech-cow]

973. K Closest Points to Origin

Problem Solving

---

Buggy Code

from heapq import heapreplace, heapify
class Solution(object):
    def kClosest(self, pairs, k):
        nums = []
        dic = {}
        self.getDist(pairs, nums, dic)
        nums = [-num for num in nums]
        heap = nums[:k]
        heapq.heapify(heap)
        
              
        for i in range(k, len(nums)):
            if nums[i] > heap[0]:
                heapq.heapreplace(heap, nums[i])
        
        res = []
        for num in heap:
            res.append(dic[-num])    
        return res
        

        
        
    
    def getDist(self, pairs, nums, dic):
        for pair in pairs:
            x, y = pair
            dist = (x ** 2 + y ** 2) ** 0.5
            dic[dist] = [x, y]
            nums.append(dist)
            
Fail:    
Input
[[0,1],[1,0]]
2
Output
[[1,0],[1,0]]
Expected
[[0,1],[1,0]]

Fixed Code

from heapq import heapreplace, heapify
class Solution(object):
    def kClosest(self, pairs, k):
        nums = []
        self.getDist(pairs, nums)
        heap = nums[:k]
        heapq.heapify(heap)
        
        for i in range(k, len(nums)):
            if -nums[i][0] < -heap[0][0]:
                heapq.heapreplace(heap, nums[i])
        
        res = []
        for num, x, y in heap:
            res.append([x, y])    
        return res
        
    def getDist(self, pairs, nums):
        for pair in pairs:
            x, y = pair
            dist = (x ** 2 + y ** 2) ** 0.5
            nums.append((-dist, x, y))