w3resource

Python: Find k number of pairs which consists of one element from the first array and one element from the second array

Python heap queue algorithm: Exercise-17 with Solution

You are given two integer arrays sorted in ascending order and an integer k. Write a Python program to find k number of pairs (u, v) which consists of one element from the first array and one element from the second array using Heap queue algorithm.

Sample Solution:

Python Code:

import heapq
def k_Smallest_Pairs(nums1, nums2, k):
   queue = []
   def push(i, j):
       if i < len(nums1) and j < len(nums2):
           heapq.heappush(queue, [nums1[i] + nums2[j], i, j])
   push(0, 0)
   pairs = []
   while queue and len(pairs) < k:
       _, i, j = heapq.heappop(queue)
       pairs.append([nums1[i], nums2[j]])
       push(i, j + 1)
       if j == 0:
           push(i + 1, 0)
   return pairs
nums1 = [1,3,7]
nums2 = [2,4,6]
k = 2
result = k_Smallest_Pairs(nums1, nums2, k)
print(result)

Sample Output:

[[1, 2], [1, 4]]

Flowchart:

Python heap queue algorithm: Find k number of pairs which consists of one element from the first array and one element from the second array.

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:


Python Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a Python program which add integer numbers from the data stream to a heapq and compute the median of all elements.
Next: Write a Python program to find the nth ugly number using Heap queue algorithm.

What is the difficulty level of this exercise?

Test your Python skills with w3resource's quiz

Python: Tips of the Day

Creates a dictionary with the same keys as the provided dictionary and values generated by running the provided function for each value:

Example:

def tips_map_values(obj, fn):
  ret = {}
  for key in obj.keys():
    ret[key] = fn(obj[key])
  return ret
users = {
  'Owen': { 'user': 'Owen', 'age': 29 },
  'Eddie': { 'user': 'Eddie', 'age': 15 }
}

print(tips_map_values(users, lambda u : u['age'])) # {'Owen': 29, 'Eddie': 15}

Output:

{'Owen': 29, 'Eddie': 15}