#0294

Valid Sudoku Board

MediumDSA28 min20 XP

Problem

Given a 9x9 board containing digits "1" through "9" and "." for empty cells, return True if no row, column, or 3x3 box contains a repeated digit.

Why This Matters

Sudoku validation is a clean example of mapping 2D coordinates to constraint groups.

Function Signature

def is_valid_sudoku(board):

Examples

Example 1

Inputboard with no repeated row, column, or box digits

OutputTrue

Empty cells are ignored; only repeated filled digits matter.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def is_valid_sudoku(board):
    """
    Input example: board with no repeated row, column, or box digits
    Return: True
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return False

def is_valid_sudoku(board):
    """
    Input example: board with no repeated row, column, or box digits
    Return: True
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return False

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

Valid partial board

Inputclassic valid board

ExpectedTrue

No constraint group repeats a digit.

Repeated row digit

Inputduplicate 5 in row 0

ExpectedFalse

Two 5s in the same row make the board invalid.

Hidden Test Categories

duplicate in columnduplicate in 3x3 boxmostly empty board