10/22 large program design League referee's Diary

October 22 was sunny and it rained yesterday, so today it is still cool. It is a good weather for programming competitions.
This is the first time I made a referee. It was very interesting. Although there were too few forks in the competition (Tomcat was shut down), it was always saved. The question is-_-0 written by larva. Ray and leaderz are still very diligent, and spent a whole day out 4 and 3 respectively. Leen is a bit ~~ The last day of the competition, I arrived at more than two times.

Problem A: pagereplacement algorithm: FIFO, leaderz's question about the page replacement algorithm. This will be covered in courses on computer composition principles, operating systems, and parallel structures. This is mandatory for each course. The test site is the data structure and simulation. During the competition, it was generally difficult to understand the subject. In fact, leaderz wrote clearly, but the algorithm itself was annoying and difficult to describe. In addition, leaderz weakened the data during the competition ~~ Hint is added to help you understand this question.

Problem B: pagereplacement algorithm: LRU, the second question of leaderz, is the next page replacement algorithm of. In fact, it is not very different from the first question. Just modify it. However, if the first question does not exist, the second question will be sad.

Problem C: to be fat, the third question of leaderz is a typical bipartite graph matching algorithm.

Problem D: irreduciblenumber, a simple question pulled by Ray. It is not simple in its algorithm, but its data size is too small. It can be passed after several enumerations. The algorithm of the program is to use a bool array, then enumerate the addition of elements in the data, set the sum to false, and then traverse the array to obtain the smallest true element is the solution.

Problem E: Lazy Boy, questions such as people and Leen are really lazy. Is from N * (n-1) *... (n-k + 1).

Problem F: Mine sweepre, Ray's game of mine clearance, Ray is a fan of mine clearance. This question is not a solution for mine clearance, but simply a number. As long as we traverse this two-dimensional array, when we encounter a ray, we will add 1 to all the surrounding areas, and then directly output it.

Problem G: xql, an abnormal simulation question. Leen originally wanted to use order by for everything. Fortunately, he later found it too complicated (-_-0, he can't do it by himself ).

Problem H: molecular formula. Maybe the question is not clear? This is indeed a difficult question to understand. In fact, its test point is the idea of recursion. As long as you are familiar with writing recursive Programs, you can easily solve this problem. At the end of the game, someone started to ask this question. Unfortunately, the results were far behind.

Problem I: sticked ball is a graph theory question, corresponding to the graph theory to find the "Graph diameter ". The principle is to find the shortest distance between all vertices, and then find the maximum value in the shortest distance. Floyd is a simple method for finding all vertices at the shortest distance. It can be obtained using three for statements. However, the running time is long, but the question is not given a large amount of data. You can also use Dijkstra's algorithm to run n times to find the shortest distance of all vertices. The complexity is O (n * nlogn), which is a little faster, but the programming is large. This question was finally made by a person who took the first place.

Other students, including Xiao Zhang of the College of Science, our Xiaoye, xinxin Pang Xin, and Zheng, who do not know each other, are brave! Although it cannot be compared with the ACM competition, everyone is very positive and enthusiastic, so it is a wonderful competition. (Finally, I despise sumhat students who have been away for a few minutes-_-Convex ).