shudu

http://news.qq.com/a/20130526/005425.htm
This problem my code use just 0.107'' to get the answer.
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| 8 1 2 | 7 5 3 | 6 4 9 |
| 9 4 3 | 6 8 2 | 1 7 5 |
| 6 7 5 | 4 9 1 | 2 8 3 |
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| 1 5 4 | 2 3 7 | 8 9 6 |
| 3 6 9 | 8 4 5 | 7 2 1 |
| 2 8 7 | 1 6 9 | 5 3 4 |
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| 5 2 1 | 9 7 4 | 3 6 8 |
| 4 3 8 | 5 2 6 | 9 1 7 |
| 7 9 6 | 3 1 8 | 4 5 2 |
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