sudoku2.java

/*
Sudoku is a number-placement puzzle. The objective is to fill a 9 × 9 grid with numbers in such a way that each column, each row, 
and each of the nine 3 × 3 sub-grids that compose the grid all contain all of the numbers from 1 to 9 one time.

Implement an algorithm that will check whether the given grid of numbers represents a valid Sudoku puzzle according to the layout 
rules described above. Note that the puzzle represented by grid does not have to be solvable.
*/

boolean sudoku2(char[][] grid) {
    for(int i = 0; i < grid.length; i++){
        for(int j = 0; j < grid[0].length; j++){
            if(grid[i][j] != '.'){
                char tmp = grid[i][j];
                for(int k = j+1; k < grid[0].length; k++){
                    if(tmp == grid[i][k]){
                        return false;
                    }
                }
                for(int l = i+1; l < grid.length; l++){
                    if(tmp == grid[l][j]){
                        return false;
                    }
                }
                int x = 0;
                int y = 0;
                if(i < 3){
                    x = 0;
                }
                if(j < 3){
                    y = 0;
                }
                 if(i > 3 && i < 6){
                    x = 3;
                }
                if(j > 3 && j < 6){
                    y = 3;
                }
                 if(i  > 6){
                    x = 6;
                }
                if(j > 6){
                    y = 6;
                }
                int tmp2 = 0;
                for(int p = x; p < x+3; p++){
                    for(int g = y; g < y+3; g++){
                        if(grid[p][g] == tmp){
                            tmp2++;
                        }
                    }
                }
                if(tmp2 >= 2){
                    return false;
                }
            }
        }
    }
    return true;
}