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Search in Rotated Sorted Array at Microsoft — Interview Guide

How to approach Search in Rotated Sorted Array in a Microsoft interview: the optimal approach, what Microsoft interviewers look for, and company-specific tips.

Updated 2026-09MediumBinary Search

The problem at Microsoft

Search for a target value in an array that was sorted then rotated at an unknown pivot, in O(log n) time.

Microsoft uses this problem to assess growth mindset, collaborative, product-minded. Expect Microsoft-specific follow-ups that tie the solution back to production reasoning and the company's engineering bar.

Key concepts

At each mid, one half is always sorted; identify it by comparing nums[mid] with nums[left].
If the target lies in the sorted half, search there; otherwise search the other half.
Handle duplicates carefully — when nums[left] == nums[mid] you cannot tell which side is sorted.

Approach

def search(nums, target):
    l, r = 0, len(nums) - 1
    while l <= r:
        m = (l + r) // 2
        if nums[m] == target: return m
        if nums[l] <= nums[m]:
            if nums[l] <= target < nums[m]: r = m - 1
            else: l = m + 1
        else:
            if nums[m] < target <= nums[r]: l = m + 1
            else: r = m - 1
    return -1

What Microsoft looks for

Growth mindset — learn from feedback and failure.
Collaboration — how you work across teams.
Customer and product focus — especially for product teams.
Solid CS fundamentals in coding and design.

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