How do you solve Make a Square with the Same Color on LeetCode?

Make a Square with the Same Color (LeetCode #3127) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(1) time complexity and O(1) space complexity. Key insight: Understanding the grid structure helps in identifying possible squares quickly.

What is the time complexity of Make a Square with the Same Color?

The optimal solution for Make a Square with the Same Color runs in O(1) time and uses O(1) space. The complexity is O(1) as we are only checking a fixed number of squares (4) in a fixed-size grid (3x3).

What is the brute force solution for Make a Square with the Same Color?

The brute force approach for Make a Square with the Same Color is Brute Force, with O(n²) time complexity and O(1) space complexity. We can check every possible 2x2 square in the 3x3 grid to see if changing one cell can make all cells in that square the same color. This is straightforward but not the most efficient. The optimal Optimal Solution approach improves this to O(1).

What algorithm or data structure is used to solve Make a Square with the Same Color?

Make a Square with the Same Color uses the following concepts: Array, Matrix, Enumeration. The recommended patterns to study are: Enumeration, Grid Traversal.

What are the interview tips for Make a Square with the Same Color?

Always clarify the problem statement and constraints before jumping into coding. Think about edge cases, such as already uniform squares. Explain your thought process while coding to demonstrate your understanding.

What are common mistakes when solving Make a Square with the Same Color?

Not considering all possible 2x2 squares. Failing to account for the case where no changes are needed.

#3127

Make a Square with the Same Color

Easy

ArrayMatrixEnumerationEnumerationGrid Traversal

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(1)
Space	O(1)	O(1)

💡

Intuition

Time O(1)Space O(1)

Instead of checking each square, we can count the occurrences of 'B' and 'W' in the grid and determine if changing one cell can create a uniform 2x2 square.

⚙️

Algorithm

4 steps

1Step 1: Count the occurrences of 'B' and 'W' in the entire grid.
2Step 2: If there are at least 3 of one color in any 2x2 square, return true.
3Step 3: If there are exactly 2 of one color and 2 of the other in any square, return false.
4Step 4: If we find a configuration that allows for one change to create a uniform square, return true.

solution.py7 lines

1def canMakeSquare(grid):
2    for i in range(2):
3        for j in range(2):
4            countB = sum(grid[i+x][j+j] == 'B' for x in range(2) for y in range(2))
5            if countB >= 3:
6                return True
7    return False

ℹ

Complexity note: The complexity is O(1) as we are only checking a fixed number of squares (4) in a fixed-size grid (3x3).

1Understanding the grid structure helps in identifying possible squares quickly.
2Counting occurrences of colors can simplify the problem.

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