AhmedVargos / LeetGrokk

Grokking The Coding Interview questions mapped to Leetcode

LeetGrokk

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Premium questions

You can access premium question on lintcode.com

Patterns

https://hackernoon.com/14-patterns-to-ace-any-coding-interview-question-c5bb3357f6ed

Pattern: Sliding Window

• https://leetcode.com/problems/maximum-subarray/  (Blind)
• https://leetcode.com/problems/minimum-size-subarray-sum/
• https://leetcode.com/problems/longest-substring-with-at-most-k-distinct-characters/
• https://leetcode.com/problems/fruit-into-baskets/
• https://leetcode.com/problems/longest-substring-without-repeating-characters/ (Blind)
• https://leetcode.com/problems/longest-repeating-character-replacement/ (Blind)
• https://leetcode.com/problems/max-consecutive-ones-iii/
• https://leetcode.com/problems/permutation-in-string/
• https://leetcode.com/problems/find-all-anagrams-in-a-string/
• https://leetcode.com/problems/minimum-window-substring/ (Blind)
• https://leetcode.com/problems/substring-with-concatenation-of-all-words/

Pattern: Islands(Matrix Traversal)

• https://leetcode.com/problems/number-of-islands/ (Blind)
• https://leetcode.com/problems/max-area-of-island/
• https://leetcode.com/problems/flood-fill/
• https://leetcode.com/problems/number-of-closed-islands/
• https://leetcode.com/problems/island-perimeter/
• https://leetcode.com/problems/number-of-distinct-islands/
• https://leetcode.com/problems/detect-cycles-in-2d-grid/

Pattern: Two Pointers

• https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/
• https://leetcode.com/problems/remove-duplicates-from-sorted-array/
• https://leetcode.com/problems/squares-of-a-sorted-array/
• https://leetcode.com/problems/3sum/ (Blind)
• https://leetcode.com/problems/3sum-closest/
• https://leetcode.com/problems/3sum-smaller/
• https://leetcode.com/problems/subarray-product-less-than-k/
• https://leetcode.com/problems/sort-colors/
• https://leetcode.com/problems/4sum/
• https://leetcode.com/problems/backspace-string-compare/
• https://leetcode.com/problems/shortest-unsorted-continuous-subarray/

Pattern: Fast & Slow pointers

• https://leetcode.com/problems/linked-list-cycle/ (Blind)
• https://leetcode.com/problems/linked-list-cycle-ii/
• https://leetcode.com/problems/happy-number/
• https://leetcode.com/problems/middle-of-the-linked-list/
• https://leetcode.com/problems/palindrome-linked-list/
• https://leetcode.com/problems/reorder-list/ (Blind)
• https://leetcode.com/problems/circular-array-loop/

Pattern: Merge Intervals

• https://leetcode.com/problems/merge-intervals/ (Blind)
• https://leetcode.com/problems/insert-interval/ (Blind)
• https://leetcode.com/problems/interval-list-intersections/
• https://leetcode.com/problems/meeting-rooms/ (Blind and Premium)
• https://leetcode.com/problems/meeting-rooms-ii/ (Blind and Premium)
• https://leetcode.com/problems/maximum-profit-in-job-scheduling/
• https://leetcode.com/problems/employee-free-time/

Pattern: Cyclic Sort

• Couldn't find Cyclic Sort
• https://leetcode.com/problems/missing-number/ (Blind)
• https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/
• https://leetcode.com/problems/find-the-duplicate-number/
• https://leetcode.com/problems/find-all-duplicates-in-an-array/
• https://leetcode.com/problems/set-mismatch/
• https://leetcode.com/problems/first-missing-positive/
• https://leetcode.com/problems/kth-missing-positive-number/

Pattern: In-place Reversal of a LinkedList

• https://leetcode.com/problems/reverse-linked-list/ (Blind)
• https://leetcode.com/problems/reverse-linked-list-ii/
• https://leetcode.com/problems/reverse-nodes-in-k-group/
• Alternation to previous question
• https://leetcode.com/problems/rotate-list/

Pattern: Tree Breadth First Search

• https://leetcode.com/problems/binary-tree-level-order-traversal/ (Blind)
• https://leetcode.com/problems/binary-tree-level-order-traversal-ii/
• https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/
• https://leetcode.com/problems/average-of-levels-in-binary-tree/
• https://leetcode.com/problems/minimum-depth-of-binary-tree/
• https://leetcode.com/problems/maximum-depth-of-binary-tree/ (Not grokk but Blind)
• https://leetcode.com/problems/inorder-successor-in-bst/ (In order instead of level order)
• https://leetcode.com/problems/populating-next-right-pointers-in-each-node/
• Alternation to previous question
• https://leetcode.com/problems/binary-tree-right-side-view/

Pattern: Tree Depth First Search

• https://leetcode.com/problems/path-sum/
• https://leetcode.com/problems/path-sum-ii/
• https://leetcode.com/problems/sum-root-to-leaf-numbers/
• https://leetcode.com/problems/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree/description/
• https://leetcode.com/problems/path-sum-iii/
• https://leetcode.com/problems/diameter-of-binary-tree/
• https://leetcode.com/problems/binary-tree-maximum-path-sum/ (Blind)

Pattern: Two Heaps

• https://leetcode.com/problems/find-median-from-data-stream/ (Blind)
• https://leetcode.com/problems/sliding-window-median/
• https://leetcode.com/problems/ipo/
• https://leetcode.com/problems/find-right-interval/

Pattern: Subsets

• https://leetcode.com/problems/subsets/
• https://leetcode.com/problems/subsets-ii/
• https://leetcode.com/problems/permutations/
• https://leetcode.com/problems/letter-case-permutation/
• https://leetcode.com/problems/generate-parentheses/
• https://leetcode.com/problems/generalized-abbreviation/
• https://leetcode.com/problems/different-ways-to-add-parentheses/
• https://leetcode.com/problems/unique-binary-search-trees-ii/
• https://leetcode.com/problems/unique-binary-search-trees/

Pattern: Modified Binary Search

• https://leetcode.com/problems/binary-search/ (Blind)
• Couldn't find Ceiling of a Number
• https://leetcode.com/problems/find-smallest-letter-greater-than-target/
• https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/
• https://leetcode.com/problems/search-in-a-sorted-array-of-unknown-size/
• https://leetcode.com/problems/minimum-absolute-difference/ (Close)
• Couldn't find Bitonic Array Maximum
• Couldn't find Search Bitonic Array
• https://leetcode.com/problems/search-in-rotated-sorted-array/ (Blind)
• https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/ (Blind)

Pattern: Bitwise XOR

• https://leetcode.com/problems/single-number/
• https://leetcode.com/problems/single-number-iii/
• https://leetcode.com/problems/complement-of-base-10-integer/
• https://leetcode.com/problems/flipping-an-image/

Pattern: Top 'K' elements

• Couldn't find Top 'K' elements
• Couldn't find Kth Smallest Number
• https://leetcode.com/problems/k-closest-points-to-origin/
• https://leetcode.com/problems/minimum-cost-to-connect-sticks/
• https://leetcode.com/problems/top-k-frequent-elements/ (Blind)
• https://leetcode.com/problems/sort-characters-by-frequency/
• https://leetcode.com/problems/kth-largest-element-in-a-stream/
• https://leetcode.com/problems/find-k-closest-elements/
• https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals/
• Couldn't find Sum of Elements
• https://leetcode.com/problems/reorganize-string/
• https://leetcode.com/problems/rearrange-string-k-distance-apart/
• https://leetcode.com/problems/task-scheduler/
• https://leetcode.com/problems/maximum-frequency-stack/

Pattern: K-way merge

• https://leetcode.com/problems/merge-k-sorted-lists/ (Blind)
• Alternation to previous question
• https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/
• https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists/
• https://leetcode.com/problems/find-k-pairs-with-smallest-sums/

Pattern: 0/1 Knapsack (Dynamic Programming)

• https://www.educative.io/courses/grokking-dynamic-programming-patterns-for-coding-interviews/RM1BDv71V60 (Free)
• https://leetcode.com/problems/partition-equal-subset-sum/ or https://www.educative.io/courses/grokking-dynamic-programming-patterns-for-coding-interviews/3jEPRo5PDvx (Free)
• https://leetcode.com/problems/subarray-sum-equals-k/ (Similar) or https://www.educative.io/courses/grokking-dynamic-programming-patterns-for-coding-interviews/3j64vRY6JnR (Free)
• https://leetcode.com/problems/partition-array-into-two-arrays-to-minimize-sum-difference/
• https://leetcode.com/problems/combination-sum-ii/ or https://leetcode.com/problems/combination-sum-iv/ (Blind)
• https://leetcode.com/problems/target-sum/

Pattern: Topological Sort (Graph)

• Couldn't find Topological Sort
• https://leetcode.com/problems/course-schedule/ (Blind)
• https://leetcode.com/problems/course-schedule-ii/
• Alternation to previous question
• https://leetcode.com/problems/alien-dictionary/ (Blind and Premium)
• https://leetcode.com/problems/sequence-reconstruction/description/
• https://leetcode.com/problems/minimum-height-trees/

Pattern: Multi-threaded

• https://leetcode.com/problems/same-tree/ (Blind)
• https://leetcode.com/problems/invert-binary-tree/ (Blind)
• https://leetcode.com/problems/binary-search-tree-iterator/

Miscellaneous

• https://leetcode.com/problems/kth-largest-element-in-an-array/