How do you solve Triangle Judgement on LeetCode?

Triangle Judgement (LeetCode #610) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(n) time complexity and O(1) space complexity. Key insight: The triangle inequality theorem is crucial for determining if three lengths can form a triangle.

What is the brute force solution for Triangle Judgement?

The brute force approach for Triangle Judgement is Brute Force, with O(n) time complexity and O(1) space complexity. To determine if three line segments can form a triangle, we can check the triangle inequality theorem. This states that the sum of the lengths of any two sides must be greater than the length of the third side. We will check this condition for each row in the table. The optimal Optimal Solution approach improves this to O(n).

What algorithm or data structure is used to solve Triangle Judgement?

Triangle Judgement uses the following concepts: Database. The recommended patterns to study are: Triangle Inequality, Conditional Logic.

What are the interview tips for Triangle Judgement?

Always explain your thought process when solving problems. Make sure to test edge cases, such as negative lengths or zero. Practice writing SQL queries to become comfortable with syntax and logic.

What are common mistakes when solving Triangle Judgement?

Not checking all three conditions of the triangle inequality. Assuming that any two sides being greater than the third is sufficient.

#610

Triangle Judgement

Easy

DatabaseTriangle InequalityConditional Logic

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n)	O(n)
Space	O(1)	O(1)

💡

Intuition

Time O(n)Space O(1)

The optimal solution is essentially the same as the brute force approach, as we need to check the triangle inequality for each set of segments. However, we can optimize the query execution by ensuring we only select valid combinations directly.

⚙️

Algorithm

3 steps

1Step 1: For each row in the Triangle table, extract the values of x, y, and z.
2Step 2: Use the triangle inequality conditions to filter valid triangles directly in the SQL query.
3Step 3: Return the results with the triangle validity.

solution.py1 lines

1SELECT x, y, z, CASE WHEN (x + y > z AND x + z > y AND y + z > x) THEN 'Yes' ELSE 'No' END AS triangle FROM Triangle;

ℹ

Complexity note: The time complexity remains O(n) as we still check each row once, and the space complexity is O(1) since we are not using any additional data structures.

1The triangle inequality theorem is crucial for determining if three lengths can form a triangle.
2Checking each combination of lengths is necessary to ensure accuracy.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.