Re: Chongqing eight day old man closed 15 days to solve the world's most difficult Sudoku question
"get up at 6:30 in the morning every day until 12 at night, and often suffer from insomnia. One night I couldn't sleep. I got up at half past three in the middle of the night and continued to work. I felt better in the evening on the 16 night, so I worked hard and stayed up all night. Chen Lao's wife smiled and added, "I said at the time, if he did this again, if he didn't do it, his body would collapse first."
is not boring at all. Instead, it is very exciting. The purpose is not to solve problems, but to verify the algorithm in my manuscript. Chen Lao introduced, first step first determine 128 possible filling methods, and then try one by one, each may contain more possibilities, that is, the actual amount of operation is greater, that is, not only 128 kinds of algorithms.
the Chongqing evening news reporter saw that there were several packages of useless questions on Chen's desk, all of which were compiled. "When I did number more than 60, I thought the answer was coming out. I was so excited that the result was a clash. I didn't succeed until 86." Chen said he had cataract in his left eye, and the right eye was damaged. "Sometimes it's wrong to have a flower."
the answer is only the Sudoku
the evening newspaper published this problem long, many netizens have claimed that they have made the answer, and there are a variety of solutions, it is confusing. Sudoku, as the name suggests, is only one solution to every question. Chongqing evening news reporter carefully examined these so-called correct answers, and found that many people did not fully understand Sudoku rules. Sudoku is a large nine palaces consisting of 9 3 * 3 small nine palaces, which require a number of 9 lattices in each row, 9 vertical columns in each column, and each area (area divided by rough lines), which are filled with 1 to 9 numbers and cannot be repeated. A variety of answers are basically unable to meet the repeated requirements of each palace figure.
Computer calculus lost fun
according to the Yangzi Evening News, on July 2nd, a netizen named "gkzhong" used computer programs to solve the Sudoku, which was said to take 300 milliseconds. Nie Chongxia, who is 54 years old, has a computer origin and is currently working at the Chongqing University's audit office. He also claims to have solved the problem. He wrote the program and took 10 seconds to write the program. He said, "300 milliseconds are not possible, but not more than 10 seconds." Since computers are so easy, why bother to work hard? The netizen "Grayfox" believes that, from the beginning of the emergence of Sudoku, it is the use of paper and pen calculus. In the process of hands-on, we can get logical training and fully appreciate the fun of thinking. Use the program to solve the problem, lost the original meaning. Chen also said: "solving problems with computer programs, only the answer, no process, also can not find the law, lost a lot of fun."
learning his Chen's solution
riding, using the vertical and horizontal elimination, determine the number of only two possible positions in each small palace, called the horse riding number, and at one time can determine the number of horseback riding. In addition, in addition to the number of 6 riding horses, it can also be determined that a particular grid can only be filled in two numbers, thus producing 2 7 squares, that is, 128 possibilities, and the answer is in the 128 nets. The 128 possibilities are eliminated one by one, and the answer emerges. This method has a certain regularity compared with the random test number, but the process is quite difficult, because there will be a new small combination under each net, small combination and small combination, that is, the actual operation amount is 128 x N x N. It is also difficult to eliminate layers by stages, but the advantage is that every number of times is absolutely correct, without overthrowing it.
Sudoku
Sudoku is a digital game. It is called Sudoku. It originated in Switzerland. It was first published in 1970s by a mathematical logic game magazine in the United States. It was named Number Place. Then it was popular in Japan. In 1984, the Sudoku was named Sudoku, that is, the omission of an independent number, which is interpreted as each party. The lattice is filled with single digits. In 2004, Gao Lede, a former judge of the Hongkong high court, brought the game to Britain to become a popular mathematical puzzle in Britain, Wayne (Gould).
puzzle is the square shape of the nine palace (that is, 3 grid width * 3 grid height), and each grid is divided into a nine palace. In each small palace, fill in 1 to 9 numbers, so that the number of columns and rows per block is not repeated. Sudoku plays a simple logic and the number of arrangements is ever-changing. Many educators think Sudoku is a good way to train the brain.