DSA challenges

Practice problem statements with input format, output format, constraints and solutions.

beginner

DSA Introduction challenge

Build a small solution that uses DSA Introduction in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core dsa introduction pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Problem Solving Method challenge

Build a small solution that uses Problem Solving Method in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core problem solving method pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Time Complexity challenge

Build a small solution that uses Time Complexity in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core time complexity pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Space Complexity challenge

Build a small solution that uses Space Complexity in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core space complexity pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Big O Tradeoffs challenge

Build a small solution that uses Big O Tradeoffs in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core big o tradeoffs pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Arrays challenge

Build a small solution that uses Arrays in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core arrays pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Strings challenge

Build a small solution that uses Strings in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core strings pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Objects and Hash Maps challenge

Build a small solution that uses Objects and Hash Maps in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core objects and hash maps pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Sets and Frequency Counting challenge

Build a small solution that uses Sets and Frequency Counting in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core sets and frequency counting pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

beginner

Prefix Sum challenge

Build a small solution that uses Prefix Sum in DSA and handles one normal case plus one edge case.

Input format

Use a short text value, array, query, or sample object depending on the topic.

Output format

Print, render, or return the processed result in a readable format.

Constraints

Keep the solution under 60 lines.
Use descriptive names.
Do not depend on hidden external services.

Starter code

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}

Test cases

basic sample - valid processed result
empty or small sample - safe fallback result

Hint

Focus on the core prefix sum pattern before polishing the final output.

Solution

function uniqueValues(values) {
  const seen = new Set();
  return values.filter((value) => {
    if (seen.has(value)) return false;
    seen.add(value);
    return true;
  });
}