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binary search answer space Pattern

Pattern hubs are for building transferable solving frames. Learn the recognition signals first, then drill state definition, update rules, and edge explanation until the pattern feels stable.

database197 problemstune19/101/77 difficulty mixcategory6 linked topics

Pattern brief

Recognize first

The candidate demonstrates a clear understanding of binary search over a valid answer space.

Solve rhythm

State the active state and invariant first, explain how each update preserves them, then pressure-test with counterexamples.

Most common miss

Confusing partitioning logic can lead to incorrect median calculations.

Recognition signals

  • The candidate demonstrates a clear understanding of binary search over a valid answer space.
  • The candidate can explain how the partitioning logic helps in avoiding unnecessary merging of arrays.
  • Ask why a standard binary search fails on rotated arrays.

Solve flow

  1. 1. Define the active state/window.
  2. 2. Update state while preserving invariants.
  3. 3. Validate with edge-heavy examples.

Common misses

  • Confusing partitioning logic can lead to incorrect median calculations.
  • Attempting simple binary search without handling rotation leads to incorrect indices.
  • Using a single binary search and assuming the first match is the left boundary.

Recommended Ladder

Problem bank

binary search answer space pattern bank

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Showing 24 / 197 problems

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Median of Two Sorted Arrays

Find the median of two sorted arrays using binary search for efficient O(log(min(m, n))) time complexity.

Hard
33

Search in Rotated Sorted Array

Find the index of a target in a rotated sorted array using a careful binary search that handles pivot shifts.

Medium
34

Find First and Last Position of Element in Sorted Array

Locate the first and last index of a target in a sorted array using binary search for precise O(log n) performance.

Medium
35

Search Insert Position

Find the correct index for a target value in a sorted array using binary search, or return the position where it should …

Easy
69

Sqrt(x)

Solve the Sqrt(x) problem using binary search to find the integer square root of a number without built-in operators.

Easy
74

Search a 2D Matrix

Search a 2D matrix efficiently using binary search over its linearized index, ensuring correctness in row-major sorted a…

Medium
81

Search in Rotated Sorted Array II

Determine if a target exists in a rotated sorted array that may contain duplicates using a binary search variation effic…

Medium
153

Find Minimum in Rotated Sorted Array

Find the minimum element in a rotated sorted array using binary search to efficiently identify the point of rotation.

Medium
154

Find Minimum in Rotated Sorted Array II

Find the minimum in a rotated sorted array with possible duplicates using binary search.

Hard
162

Find Peak Element

Find Peak Element leverages binary search for efficiently locating a peak in an array, a problem commonly asked in techn…

Medium
167

Two Sum II - Input Array Is Sorted

Solve the Two Sum II problem efficiently using binary search over a valid answer space in a sorted array.

Medium
209

Minimum Size Subarray Sum

Find the minimal length of a subarray whose sum is greater than or equal to the target using efficient algorithms.

Medium
240

Search a 2D Matrix II

Efficiently search for a target in a 2D matrix using binary search and matrix properties.

Medium
275

H-Index II

Compute a researcher's H-Index from a sorted citation array using binary search over the valid answer space efficiently.

Medium
278

First Bad Version

Find the first bad version of a product using binary search, minimizing the number of API calls.

Easy
287

Find the Duplicate Number

The problem involves finding the duplicate number in an array of integers, using a binary search approach over the valid…

Medium
315

Count of Smaller Numbers After Self

Solve the Count of Smaller Numbers After Self problem using binary search and optimized algorithms.

Hard
327

Count of Range Sum

Count the number of subarray sums within a given inclusive range using optimized divide-and-conquer techniques efficient…

Hard
352

Data Stream as Disjoint Intervals

The problem involves designing a class to summarize a data stream of non-negative integers as disjoint intervals using b…

Hard
363

Max Sum of Rectangle No Larger Than K

Solve the "Max Sum of Rectangle No Larger Than K" problem using binary search over the valid sum space to optimize space…

Hard
367

Valid Perfect Square

Determine if a given positive integer is a perfect square using a binary search approach over potential square roots eff…

Easy
374

Guess Number Higher or Lower

Find the picked number efficiently using binary search while adjusting guesses based on higher or lower feedback in this…

Easy
378

Kth Smallest Element in a Sorted Matrix

Find the kth smallest element in a sorted n x n matrix using efficient binary search or heap strategies for optimized me…

Medium
400

Nth Digit

Given n, efficiently find the nth digit in the infinite integer sequence using a binary search over valid positions.

Medium

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Binary search over the valid answer space LeetCode Pattern: 197 Solutions