STARTING BOARD 

Board size: 19x19
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 15 | 2  | 5  | 16 | 11 | 1  | 8  | 16 | 14 | 18 | 13 | 20 | 17 | 9  | 17 | 10 | 19 | 16 | 13 | 3  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 13 | 11 | 3  | 2  | 3  | 6  | 2  | 18 | 13 | 12 | 14 | 12 | 19 | 5  | 4  | 18 | 10 | 18 | 9  | 15 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 4  | 10 | 20 | 4  | 3  | 8  | 14 | 19 | 13 | 9  | 4  | 6  | 11 | 3  | 7  | 4  | 2  | 12 | 16 | 5  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 1  | 15 | 17 | 6  | 18 | 5  | 3  | 8  | 5  | 4  | 11 | 16 | 10 | 14 | 2  | 13 | 20 | 19 | 12 | 7  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 13 | 18 | 8  | 4  | 16 | 20 | 10 | 10 | 11 | 5  | 19 | 17 | 8  | 14 | 3  | 9  | 5  | 1  | 2  | 17 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 2  | 4  | 16 | 12 | 4  | 10 | 10 | 5  | 20 | 15 | 9  | 14 | 9  | 17 | 17 | 8  | 16 | 4  | 4  | 11 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 9  | 8  | 5  | 3  | 4  | 14 | 12 | 1  | 11 | 13 | 20 | 2  | 15 | 11 | 2  | 14 | 17 | 8  | 19 | 16 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 14 | 4  | 12 | 20 | 2  | 11 | 19 | 1  | 10 | 5  | 17 | 1  | 2  | 8  | 16 | 11 | 15 | 6  | 5  | 18 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 7  | 5  | 14 | 3  | 8  | 14 | 6  | 12 | 15 | 4  | 10 | 9  | 18 | 10 | 17 | 20 | 3  | 2  | 11 | 11 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 8  | 9  | 4  | 10 | 5  | 7  | 11 | 16 | 16 | 6  | 13 | 17 | 13 | 12 | 9  | 19 | 17 | 20 | 8  | 14 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 15 | 16 | 11 | 3  | 5  | 3  | 17 | 2  | 14 | 14 | 4  | 4  | 3  | 10 | 13 | 12 | 12 | 19 | 13 | 20 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 17 | 4  | 19 | 14 | 17 | 12 | 3  | 18 | 8  | 1  | 6  | 13 | 15 | 11 | 11 | 6  | 9  | 16 | 20 | 6  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 20 | 19 | 12 | 7  | 5  | 9  | 16 | 4  | 12 | 11 | 16 | 18 | 17 | 3  | 1  | 17 | 6  | 10 | 13 | 8  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 5  | 6  | 10 | 18 | 12 | 13 | 4  | 11 | 19 | 17 | 3  | 15 | 2  | 5  | 8  | 1  | 10 | 14 | 9  | 5  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 8  | 10 | 9  | 13 | 18 | 2  | 7  | 11 | 4  | 3  | 15 | 8  | 20 | 16 | 5  | 12 | 14 | 8  | 10 | 6  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 4  | 12 | 6  | 17 | 13 | 15 | 7  | 5  | 1  | 14 | 17 | 11 | 17 | 19 | 14 | 18 | 7  | 5  | 15 | 11 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 7  | 17 | 9  | 5  | 6  | 14 | 13 | 9  | 1  | 10 | 6  | 14 | 4  | 9  | 20 | 1  | 11 | 8  | 1  | 19 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 18 | 4  | 1  | 19 | 10 | 17 | 19 | 6  | 7  | 1  | 9  | 4  | 16 | 2  | 11 | 5  | 4  | 13 | 7  | 12 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 17 | 13 | 2  | 3  | 6  | 15 | 9  | 10 | 15 | 20 | 3  | 5  | 6  | 18 | 12 | 4  | 4  | 7  | 14 | 1  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 1  | 7  | 3  | 18 | 20 | 15 | 11 | 17 | 6  | 19 | 6  | 10 | 12 | 12 | 14 | 16 | 3  | 9  | 1  | 13 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
FINAL SOLUTION 

+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 2  | 5  | ■  | 11 | 1  | 8  | ■  | 14 | 18 | 13 | 20 | ■  | 9  | ■  | 10 | 19 | 16 | ■  | 3  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 13 | 11 | 3  | 2  | ■  | 6  | ■  | 18 | ■  | 12 | 14 | ■  | 19 | 5  | 4  | ■  | 10 | ■  | 9  | 15 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 10 | 20 | ■  | 3  | 8  | 14 | 19 | 13 | 9  | ■  | 6  | 11 | ■  | 7  | 4  | ■  | 12 | 16 | ■  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 1  | 15 | 17 | 6  | ■  | 5  | ■  | 8  | ■  | 4  | 11 | 16 | 10 | 14 | ■  | 13 | 20 | ■  | 12 | 7  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 18 | ■  | 4  | 16 | 20 | 10 | ■  | 11 | ■  | 19 | ■  | 8  | ■  | 3  | 9  | 5  | 1  | 2  | ■  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 2  | ■  | 16 | 12 | ■  | 10 | ■  | 5  | 20 | 15 | ■  | 14 | 9  | 17 | ■  | 8  | ■  | 4  | ■  | 11 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 9  | 8  | ■  | 3  | 4  | ■  | 12 | 1  | ■  | 13 | 20 | ■  | 15 | ■  | 2  | 14 | 17 | ■  | 19 | 16 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 14 | ■  | 12 | 20 | 2  | 11 | 19 | ■  | 10 | 5  | ■  | 1  | ■  | 8  | 16 | ■  | 15 | 6  | ■  | 18 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 7  | 5  | 14 | ■  | 8  | ■  | 6  | 12 | 15 | ■  | 10 | 9  | 18 | ■  | 17 | 20 | 3  | ■  | 11 | ■  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 9  | 4  | 10 | ■  | 7  | 11 | ■  | 16 | 6  | ■  | 17 | ■  | 12 | ■  | 19 | ■  | 20 | 8  | 14 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 15 | 16 | 11 | ■  | 5  | ■  | 17 | 2  | ■  | 14 | 4  | ■  | 3  | 10 | 13 | ■  | 12 | 19 | ■  | 20 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 4  | 19 | 14 | 17 | 12 | 3  | ■  | 8  | 1  | ■  | 13 | ■  | 11 | ■  | 6  | 9  | ■  | 20 | ■  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 20 | 19 | ■  | 7  | ■  | 9  | ■  | 4  | 12 | ■  | 16 | 18 | 17 | 3  | 1  | ■  | 6  | 10 | 13 | 8  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 6  | 10 | ■  | 12 | 13 | 4  | ■  | 19 | 17 | ■  | 15 | 2  | ■  | 8  | 1  | ■  | 14 | ■  | 5  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 8  | ■  | 9  | 13 | 18 | 2  | ■  | 11 | 4  | 3  | 15 | ■  | 20 | 16 | 5  | 12 | 14 | ■  | 10 | 6  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 4  | 12 | 6  | ■  | 13 | ■  | 7  | ■  | 1  | ■  | 17 | 11 | ■  | 19 | ■  | 18 | ■  | 5  | 15 | ■  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 17 | ■  | 5  | ■  | 14 | 13 | 9  | ■  | 10 | 6  | ■  | 4  | ■  | 20 | ■  | 11 | 8  | 1  | 19 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 18 | ■  | 1  | 19 | 10 | 17 | ■  | 6  | 7  | ■  | 9  | 4  | 16 | 2  | 11 | 5  | ■  | 13 | ■  | 12 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| 17 | 13 | 2  | ■  | 6  | ■  | 9  | 10 | ■  | 20 | 3  | 5  | ■  | 18 | 12 | ■  | 4  | 7  | 14 | 1  |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+
| ■  | 7  | ■  | 18 | 20 | 15 | ■  | 17 | 6  | 19 | ■  | 10 | 12 | ■  | 14 | 16 | ■  | 9  | ■  | 13 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+