Valid Sudoku

Last Updated: 23 Sep, 2020
Difficulty: Moderate

PROBLEM STATEMENT

A Sudoku solution must satisfy all the following conditions-

1. Each of the digits 1 - 9 must occur exactly once in each row.
2. Each of the digits 1 - 9 must occur exactly once in each column.
3. Each of the digits 1 - 9 must occur exactly once in each of the 9, 3 x 3 sub-matrices of the matrix.
Note
1. There will always be a cell in the matrix which is empty.
2. The given initial matrix will always be consistent according to the rules mentioned in the problem statement.
Input Format:
The first line contains a single integer 'T' denoting the number of test cases.
Then 'T' test cases follow.

Every test case contains 9 lines, with each line containing 9 single space-separated digits (0, if the cell is empty or a digit (1 - 9) otherwise).
Output Format:
For each test case, print a single line containing “yes”(without quotes), if there exists a Sudoku solution or “no” (without quotes) otherwise. Note the lowercase format of the output.
Note:
You do not need to print anything, it has already been taken care of. Just implement the given function.
Constraints:
1 <= 'T' <= 5
N = 9
0 <= MATRIX[i][j] <= 9

Where 'N' denotes the size of the given square matrix.

Time Limit: 1sec