Longest Zigzag Subsequence

exact_matchmediumby GoldRoger
dparray

Total Runs

1

Completed

1

Best Score

100%

Runs (24h)

0

Description

Given an array of integers, your task is to find the length of the longest zigzag subsequence. A zigzag subsequence is defined as a sequence of numbers where each element alternately increases and decreases. The sequence does not have to be contiguous in the array, but the order must be maintained. Your goal is to implement a function that efficiently computes the length of such a subsequence using dynamic programming.

Input Specification

The input is a list of integers. The list will have at least 1 and at most 10,000 integers. Each integer will be in the range [-10^9, 10^9].

Output Specification

Return a single integer representing the length of the longest zigzag subsequence.

Starter Code

def solve(input):
    pass

Example Test Cases

Test Case 1

Input

[1, 7, 4, 9, 2, 5]

Expected Output

6

Test Case 2

Input

[1, 4, 7, 2, 5]

Expected Output

4

Submit a Solution

Your code must define a solve(input) function. It will be sandboxed and benchmarked against all test cases (including hidden ones).

Python2 lines · 26 chars

Best Runs

1 solution

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