How do you solve Check if Grid Satisfies Conditions on LeetCode?

Check if Grid Satisfies Conditions (LeetCode #3142) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(m + n) time complexity and O(1) space complexity. Key insight: Each column must have the same value.

What is the brute force solution for Check if Grid Satisfies Conditions?

The brute force approach for Check if Grid Satisfies Conditions is Brute Force, with O(m * n) time complexity and O(1) space complexity. We will check each cell in the grid to see if it meets the conditions. For each cell, we will compare it with the cell below and the cell to the right, if they exist. The optimal Optimal Solution approach improves this to O(m + n).

What algorithm or data structure is used to solve Check if Grid Satisfies Conditions?

Check if Grid Satisfies Conditions uses the following concepts: Array, Matrix. The recommended patterns to study are: Array, Matrix.

What are the interview tips for Check if Grid Satisfies Conditions?

Clarify the problem statement and constraints before coding. Consider edge cases like single row or column grids. Explain your thought process while coding to show understanding.

What are common mistakes when solving Check if Grid Satisfies Conditions?

Not checking bounds when accessing grid elements. Confusing equality checks with inequality checks.

#3142

Check if Grid Satisfies Conditions

Easy

ArrayMatrixArrayMatrix

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

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

💡

Intuition

Time O(m + n)Space O(1)

We can optimize our checks by first ensuring that all cells in each column are the same. If this condition is satisfied, we only need to check adjacent columns for differences in their first cells.

⚙️

Algorithm

5 steps

1Step 1: Iterate through each column to check if all cells in that column are the same.
2Step 2: If any column fails this check, return false.
3Step 3: If all columns pass, check the first cell of each column to ensure they are different.
4Step 4: If any adjacent columns have the same first cell, return false.
5Step 5: If all checks pass, return true.

solution.py12 lines

1# Full working Python code
2
3def checkGrid(grid):
4    m, n = len(grid), len(grid[0])
5    for j in range(n):
6        for i in range(1, m):
7            if grid[i][j] != grid[i - 1][j]:
8                return False
9    for j in range(n - 1):
10        if grid[0][j] == grid[0][j + 1]:
11            return False
12    return True

ℹ

Complexity note: The optimal solution checks each column for equality and then checks adjacent columns for differences, leading to a time complexity of O(m + n). The space complexity remains O(1) as we are not using additional data structures.

1Each column must have the same value.
2Adjacent columns must have different values.

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