This Challenge is derived from GJam 2014 China Sudoku. Large Case.

The Goal is determine if the Sudoku square is valid. Each row and column must contain 1:N, for an NxN matix. Nroot=N^.5. Each NrootxNroot block must contain 1:N where blocks start at [1,1+Nroot,...] in Row/Col.

Input: [M], NxN matrix (3^2<=N<=6^2)

Output: TF, 1=Valid, 0=Invalid

Examples:

TF=1
5 3 4 6 7 8 9 1 2
6 7 2 1 9 5 3 4 8
1 9 8 3 4 2 5 6 7
8 5 9 7 6 1 4 2 3
4 2 6 8 5 3 7 9 1
7 1 3 9 2 4 8 5 6
9 6 1 5 3 7 2 8 4
2 8 7 4 1 9 6 3 5
3 4 5 2 8 6 1 7 9
TF=0
5 3 4 6 7 8 9 1 2
6 7 2 1 9 5 3 4 8
1 9 8 3 4 2 5 6 7
8 5 9 7 6 1 4 2 3
4 2 6 8 999 3 7 9 1
7 1 3 9 2 4 8 5 6
9 6 1 5 3 7 2 8 4
2 8 7 4 1 9 6 3 5
3 4 5 2 8 6 1 7 9

Contest Performance: Best Delta Time of 7 minutes with 1146 of 2010 able to process the large data set.

Solution Stats

154 Solutions

66 Solvers

Last Solution submitted on Dec 15, 2025

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