LeetCode 75: All 75 Problems, 22 Topics, and What It Leaves Out

LeetCode 75 is the official study plan published by LeetCode, and every problem in it is free. It holds 75 problems in 22 topic groups, positioned for one to three months of preparation. Completing it earns a badge on your profile.

The detail most summaries omit is the difficulty split. Of the 75 problems, 22 are rated Easy, 53 are rated Medium, and not one is rated Hard. That single fact decides whether the plan suits you, and the rest of this guide works through what it means.

Below you will find all 75 problems grouped by topic, each with the key move that solves it and a link to a full explanation where we have one. You will also find the three things the plan does not advertise: the missing Hard tier, the nine problems it shares with Blind 75, and the 21 interview patterns it never touches.

The plan in numbers

A note on the name before we go further. LeetCode 75 is not Blind 75, and it is not Grind 75. All three are different lists, and the two 75-problem lists overlap by only nine problems. The comparison section below sets them side by side.

It contains no Hard problems

LeetCode lists 4,081 problems, of which 982 are rated Hard. The plan draws on none of them.

LeetCode 75 next to the whole platform. The plan stops at Medium.

This is the most consequential property of LeetCode 75 and the one most rarely stated. The practical reading is straightforward. The plan prepares you well for a screening round and for a typical mid-level loop, where Easy and Medium questions carry most of the weight. It does not prepare you for the Hard question that senior and staff loops frequently include.

So treat the list as a starting point rather than a finishing line. If you are targeting a senior title, finish the plan and then work a Hard tier separately, by pattern rather than at random. A reasonable source for that is Blind 75 grouped by pattern. It includes genuine Hard problems such as Minimum Window Substring, Word Search II, and Serialize and Deserialize Binary Tree.

It shares only nine problems with Blind 75

Both lists are called "75" and candidates reasonably assume they are near duplicates. They are not. Exactly nine problems appear on both:

• Product of Array Except Self
• Container With Most Water
• Counting Bits
• Longest Common Subsequence
• House Robber
• Unique Paths
• Non-overlapping Intervals
• Maximum Depth of Binary Tree
• Implement Trie

The other 66 on each list are different problems. Finishing one list therefore leaves most of the other unsolved, which is worth knowing before you pick.

Two lists of 75, and only nine problems in common.

The reason is editorial. LeetCode describes its selection as essential and trending, and the contents reflect that. Several questions interviewers ask constantly are absent from LeetCode 75, including Two Sum, Valid Parentheses, Merge Intervals, and Number of Islands. The substitutes teach the same techniques, but they rarely appear verbatim in an interview. Dota2 Senate and Reorder Routes to Make All Paths Lead to the City Zero are two examples. That choice is defensible as teaching and a weakness as rehearsal.

How it compares with the other named lists

Top Interview 150 is the thorough plan from the same publisher. It holds 150 problems across 23 groups, split 39 Easy, 93 Medium, and 18 Hard, and LeetCode positions it for three months or more. So the choice between the two official plans is governed by the time you have, not by quality. Take LeetCode 75 at one to three months and Top Interview 150 beyond that.

For a direct comparison of the competing 75-problem lists, see Blind 75 vs NeetCode 150 vs Grokking 75.

The 21 patterns it does not cover

A coding interview tests pattern recognition, so the useful question about any list is which patterns it exercises. We mapped all 75 problems against the 41 patterns taught in Grokking the Coding Interview, which splits into 30 common patterns and 11 advanced ones.

LeetCode 75 exercises 20 of the 30 common patterns and none of the 11 advanced ones. So 21 of 41 are absent. The ten common patterns it misses are:

• Cyclic Sort
• Two Heaps
• Subsets
• K-way Merge
• Greedy
• Palindromic Subsequence
• Topological Sort
• Union Find
• Ordered Set
• Multi-threaded

Several of those appear regularly in real loops. Topological sort shows up as course scheduling, union find as connectivity, subsets as combination generation, and two heaps as the running median. A candidate who finishes LeetCode 75 and meets one of them is meeting it for the first time.

Twenty of the 41 patterns are exercised. The ten common ones it skips are named on the right.

This is not an argument against the plan. It is an argument for knowing the boundary of what you have covered. The full map of techniques is in the most common LeetCode patterns and the longer treatment in LeetCode patterns you need to know.

All 75 problems, by topic group

The plan is organized by technique rather than by data structure, which is its single best property. Each group is small enough to finish in one or two study sessions.

Each table below gives the problem, its difficulty, the key move that solves it, and where we cover it. "Full explanation" links to a free write-up with a worked solution. "Course lesson" links to the lesson that teaches it inside a course. "Pattern guide" means we have no page for that specific problem yet, so the link goes to the guide for the technique it uses.

Array and string

The warm-up group, and the largest. These questions test whether you can index carefully and scan once rather than twice. Nothing here needs a named data structure. 9 problems in this group: 5 Easy, 4 Medium.

Two Pointers

Two indices move over the same input, either inward from both ends or at different speeds. The signal is a sorted array, a pair to find, or a partition to maintain in place. 4 problems in this group: 2 Easy, 2 Medium.

Sliding Window

A contiguous run of elements whose two edges both move forward. The signal is the words subarray or substring together with a length or a budget. 4 problems in this group: 1 Easy, 3 Medium.

Prefix Sum

Precompute running totals so any range answer becomes one subtraction. The signal is repeated questions about ranges, or a split point. 2 problems in this group: 2 Easy.

Hash map and set

Trade memory for lookup time. The signal is counting, membership, or grouping by a derived key. 4 problems in this group: 2 Easy, 2 Medium.

Stack

Last in, first out, which suits nesting and pairing. The signal is brackets, undo behavior, or an element that cancels an earlier one. 3 problems in this group: 3 Medium.

Queue

First in, first out, for order preserved over time. Only two problems here, and both are simulations. 2 problems in this group: 1 Easy, 1 Medium.

Linked List

Pointer surgery without extra arrays. The signal is a middle, a cycle, a reversal, or a reorder, all done in place. 4 problems in this group: 1 Easy, 3 Medium.

Binary tree, depth first search

Recursion that goes deep before wide. The signal is a path, a depth, or an answer that combines results from both subtrees. 6 problems in this group: 2 Easy, 4 Medium.

Binary tree, breadth first search

Level by level with a queue. The signal is the word level, or anything about what is visible from one side. 2 problems in this group: 2 Medium.

Binary Search Tree

The ordering invariant turns search into a single descent. The signal is the phrase binary search tree itself. 2 problems in this group: 1 Easy, 1 Medium.

Graphs, depth first search

Connectivity and reachability over an explicit graph. The signal is components, provinces, or following edges to a conclusion. 4 problems in this group: 4 Medium.

Graphs, breadth first search

Shortest number of steps on an unweighted graph, including a grid. The signal is minimum time or fewest moves. 2 problems in this group: 2 Medium.

Heap and priority queue

Keep only the best k, or always pull the current extreme. The signal is kth largest, top k, or a repeated minimum. 4 problems in this group: 4 Medium.

Binary Search

Halve a monotonic search space. The space is sometimes the array, and sometimes the answer itself. 4 problems in this group: 1 Easy, 3 Medium.

Backtracking

Build a candidate, recurse, then undo the last choice. The signal is all combinations, all permutations, or all subsets. 2 problems in this group: 2 Medium.

Dynamic programming, one dimensional

One state per position, built from a small number of earlier positions. The signal is counting ways or optimizing over a sequence. 4 problems in this group: 2 Easy, 2 Medium.

Dynamic programming, multidimensional

A table over two inputs or a grid. The signal is two strings to compare, or a path across a grid. 4 problems in this group: 4 Medium.

Bit Manipulation

Work on the binary representation directly. The signal is pairing, parity, or a constant-space requirement. 3 problems in this group: 2 Easy, 1 Medium.

Trie

A tree keyed by character, for prefix questions. The signal is autocomplete, prefix search, or a dictionary of words. 2 problems in this group: 2 Medium.

Intervals

Sort first, then make one greedy pass. The signal is overlap, merging, or a minimum number of removals. 2 problems in this group: 2 Medium.

Monotonic Stack

A stack whose values only rise or only fall, so each pop answers an earlier element. The signal is next greater or previous smaller. 2 problems in this group: 2 Medium.

A schedule for four, eight, and twelve weeks

LeetCode positions the plan at one to three months and leaves the pacing to you. Seventy-five problems divide cleanly:

Work the groups in the order above rather than by difficulty. The order is deliberate: arrays and strings build the indexing habits, two pointers and sliding window build the scanning habits, and the tree and graph groups depend on both. Dynamic programming sits late for the same reason.

Two rules make the difference between finishing the list and learning from it. First, name the technique out loud before you write any code, and only then write it. Second, when you cannot name it, read the explanation rather than the solution, and come back to the problem a day later. For concrete daily numbers across different targets, see how many LeetCode problems to solve per day and how long a list takes to finish.

What a problem list cannot teach you

A plan is a sequence of problems, and a sequence of problems is not a method. LeetCode 75 tells you which questions to solve and which topic each one belongs to. It does not teach you to recognize the technique from a problem statement you have never seen before. That recognition is the skill an interviewer actually measures.

This is why two candidates who both finished the same 75 problems can perform very differently. One learned 75 solutions. The other learned 22 techniques and the signals that point to each. The first candidate stalls the moment the wording changes, and interviewers change the wording deliberately.

The practical fix is to work any list with the patterns in front of you rather than behind you. Read the group note before the problems in that group, state which signal in the statement points to the technique, and only then solve. The reasoning behind that approach is covered in why LeetCode feels so difficult and why solving problems alone is not enough.

Frequently asked questions

Is LeetCode 75 free? Yes. Every problem in the plan is free, and none of the 22 groups is Premium-locked. The plan itself is therefore not a reason to subscribe. For what a subscription does change, see is LeetCode Premium worth buying and LeetCode Premium versus free.

Does LeetCode 75 include Hard problems? No. The split is 22 Easy and 53 Medium, with zero Hard. If your loop will include a Hard question, add that tier separately.

Is LeetCode 75 enough for FAANG? It is enough to be ready for a screening round and a mid-level loop, and it is not enough on its own for a senior one. Two gaps matter: the absent Hard tier, and the ten common patterns listed above. Finish the plan, then close those two gaps.

LeetCode 75 or Blind 75? They share only nine problems, so this is a real choice rather than a preference. Pick LeetCode 75 for a guided plan with a badge and newer problems. Pick Blind 75 for the classic canon, which includes the questions interviewers most often ask verbatim. Doing both is 141 distinct problems, which is a different commitment.

How long does LeetCode 75 take? LeetCode suggests one to three months. The table above converts that into about 3 problems a day at four weeks, or about 1 a day at twelve.

Is there a LeetCode 75 PDF or sheet? LeetCode does not publish one. The tables on this page are the list in full, including the pattern behind each problem, so this page serves the same purpose and stays current. For a one-page reference across all the patterns rather than this one list, see the DSA patterns cheat sheet.

Are there Python solutions? Every problem we have written up carries a runnable solution. The "Full explanation" links in the tables above lead to those pages, 29 of them at the time of writing, and we are adding the rest.

What is the LeetCode 75 badge? LeetCode awards a profile badge for completing the plan. It is a completion marker and nothing more. No interviewer will ask about it.

Is LeetCode 75 the same as a 75-day challenge? No. Those are unrelated community challenges that happen to use the number 75. LeetCode 75 is a fixed set of 75 problems with no time requirement attached.

Where to go after the plan

Finish the 75, then do three things in this order. Close the pattern gaps listed above, because they are the ones most likely to appear and least likely to be familiar. Add a Hard tier, worked by pattern. Then move to Top Interview 150 if you still have time, since it is the same publisher's thorough plan and includes 18 Hard problems.

You may prefer to learn the techniques in a structured order, then practice on any list. In that case, Grokking the Coding Interview teaches each pattern in its own chapter. That order is what makes a list like this one faster to work through. The curated 75 that follows that order is Grokking 75.

The figures on this page were read from LeetCode's own study plan data. You can open the plan at leetcode.com/studyplan/leetcode-75.