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Grokking the Coding Interview Patterns in Python

Longest Consecutive Sequence

Explore methods to find the longest consecutive sequence in an unsorted array by using Union Find patterns. Understand how to implement efficient solutions in Python and practice your coding interview skills by connecting problem traits with graph connectivity techniques.

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Statement

Given an unsorted array, nums, your task is to return the length of the longest consecutive sequence of elements. The consecutive sequence of elements is such that there are no missing elements in the sequence. The consecutive elements can be present anywhere in the input array.

Note: Two elements, xx and yy, are called consecutive if the difference between them is equal to 11.

Constraints:

  • 0≤0 \leq nums.lengths ≤103\leq 10^{3}
  • −106≤-10^{6} \leq nums[i] ≤106\leq 10^{6}

Examples

Understand the problem

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

Longest Consecutive Sequence

1.

What is the output if the following numbers array is given as input?

nums = [1,3,2][1, 3, 2]

A.

11

B.

00

C.

33

D.

44

1 / 4

Figure it out!

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Sequence - Vertical
Drag and drop the cards to rearrange them in the correct sequence.
1
2
3
4

Try it yourself

Implement your solution in main.py in the following coding playground. The supporting code template provided in union_find.py is meant to assist in developing your solution to the problem.

Python
usercode > main.py
"""

⬅️ We have provided a union_find.py file under the "Files" tab 

of this widget. You can use this file to build your solution.

"""

from union_find import UnionFind



def longest_consecutive_sequence(nums):



    # Replace this placeholder return statement with your code

    

    return 0
Longest Consecutive Sequence