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mystery2d4

Language/Type: Java 2D arrays array mystery
Author: Marty Stepp (on 2021/04/02)

Consider the following method: 

            public Set mystery4(int[][] data, int pos, int n) {
                Set result = new TreeSet<>();
                for (int i = 0; i < n; i++) {
                    for (int j = 0; j < n; j++) {
                        result.add(data[i + pos][j + pos]);
                    }
                }
                return result;
            }

Suppose that a variable called grid has been declared as follows: 

           int[][] grid = {{8, 2, 7, 8, 2, 1}, {1, 5, 1, 7, 4, 7},
                           {5, 9, 6, 7, 3, 2}, {7, 8, 7, 7, 7, 9},
                           {4, 2, 6, 9, 2, 3}, {2, 2, 8, 1, 1, 3}};

which means it will store the following 6-by-6 grid of values: 

            8       2       7       8       2       1       
            1       5       1       7       4       7       
            5       9       6       7       3       2       
            7       8       7       7       7       9       
            4       2       6       9       2       3       
            2       2       8       1       1       3

For each call below, indicate what value is returned. If the method call results in an exception being thrown, write "exception" instead.

mystery4(grid, 2, 2)
mystery4(grid, 0, 2)
mystery4(grid, 3, 3)

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