Completed Sudoku Validator

You are given a 9x9 grid matrix completely filled with integers from 1 to 9. Return whether it is a valid completed Sudoku board.

A completed Sudoku board is valid when:

• every row contains each digit 1 to 9 exactly once
• every column contains each digit 1 to 9 exactly once
• every one of the nine 3x3 boxes (formed by dividing the grid into a 3x3 arrangement of 3x3 subgrids) contains each digit 1 to 9 exactly once

Examples

Example 1

Input: matrix = [[1,2,3,4,5,6,7,8,9],[4,5,6,7,8,9,1,2,3],[7,8,9,1,2,3,4,5,6],[2,3,4,5,6,7,8,9,1],[5,6,7,8,9,1,2,3,4],[8,9,1,2,3,4,5,6,7],[3,4,5,6,7,8,9,1,2],[6,7,8,9,1,2,3,4,5],[9,1,2,3,4,5,6,7,8]]
Output: true

Example 2

Input: matrix = [[2,2,3,4,5,6,7,8,9],[4,5,6,7,8,9,1,2,3],[7,8,9,1,2,3,4,5,6],[2,3,4,5,6,7,8,9,1],[5,6,7,8,9,1,2,3,4],[8,9,1,2,3,4,5,6,7],[3,4,5,6,7,8,9,1,2],[6,7,8,9,1,2,3,4,5],[9,1,2,3,4,5,6,7,8]]
Output: false
Explanation: The first row now has two 2s and no 1, so it is no longer a valid row (and the top-left box is also broken the same way).

Example 3

Input: matrix = [[1,2,3,4,5,6,7,8,9],[2,3,4,5,6,7,8,9,1],[3,4,5,6,7,8,9,1,2],[4,5,6,7,8,9,1,2,3],[5,6,7,8,9,1,2,3,4],[6,7,8,9,1,2,3,4,5],[7,8,9,1,2,3,4,5,6],[8,9,1,2,3,4,5,6,7],[9,1,2,3,4,5,6,7,8]]
Output: false
Explanation: Every row and every column here contains each digit exactly once, but the top-left 3x3 box has values 1,2,3,2,3,4,3,4,5, which repeats 2, 3, and 4 while missing 6, 7, 8, and 9.