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Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

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This is a medium difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Google.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Google during technical interviews.

Find longest increasing contiguous subarray

Q: Find longest increasing contiguous subarray

This question evaluates proficiency in array processing and algorithmic optimization, focusing on recognition of contiguous subarray properties and handling a single-value modification to achieve strict monotonicity.

Problem

You are given an integer array nums (length n).

Part 1

Find the length of the longest contiguous subarray that is strictly increasing (i.e., for every adjacent pair in the subarray, a[i] < a[i+1]).

Input: nums: int[]

Output: maxLen: int

Example:

nums = [1, 2, 2, 3, 4] → longest strictly increasing contiguous subarray is [2,3,4] , so maxLen = 3 .

Follow-up

Now suppose you may modify (replace) the value of at most one element within a chosen contiguous subarray (replace it with any integer value you want) in order to make that subarray strictly increasing.

Return the maximum possible length of a contiguous subarray that can be made strictly increasing with ≤ 1 replacement.

Clarification/assumption (make explicit in interview): The replacement value is unconstrained (can be any integer), and you are asked only for the maximum achievable length.

Example idea:

nums = [1, 5, 3, 4] → by replacing 5 with 2 , the whole array can become [1,2,3,4] , so answer is 4 .

Constraints (reasonable interview defaults)

1 <= n <= 2e5
-1e9 <= nums[i] <= 1e9
Aim for better than O(n^2) in the follow-up.

Problem

You are given an integer array nums (length n).

Part 1

Find the length of the longest contiguous subarray that is strictly increasing (i.e., for every adjacent pair in the subarray, a[i] < a[i+1]).

Input: nums: int[]

Output: maxLen: int

Example:

nums = [1, 2, 2, 3, 4] → longest strictly increasing contiguous subarray is [2,3,4] , so maxLen = 3 .

Follow-up

Return the maximum possible length of a contiguous subarray that can be made strictly increasing with ≤ 1 replacement.

Clarification/assumption (make explicit in interview): The replacement value is unconstrained (can be any integer), and you are asked only for the maximum achievable length.

Example idea:

nums = [1, 5, 3, 4] → by replacing 5 with 2 , the whole array can become [1,2,3,4] , so answer is 4 .

Constraints (reasonable interview defaults)

1 <= n <= 2e5

-1e9 <= nums[i] <= 1e9

Aim for better than O(n^2) in the follow-up.

Find longest increasing contiguous subarray

Quick Overview

Problem

Part 1

Follow-up

Constraints (reasonable interview defaults)

Submit Your Answer to Earn 20XP

Find longest increasing contiguous subarray

Quick Overview

Problem

Part 1

Follow-up

Constraints (reasonable interview defaults)

Submit Your Answer to Earn 20XP