Background The knight is getting bored of seeing the same black and white squares again and again and has decided to make a journey around the world. Whenever a knight moves, it is two squares in one direction and one square perpendicular to this. The world of a knight is the chessboard he is living on. Our knight lives on a chessboard that has a smaller area than a regular 8 * 8 board, but it is still rectangular. Can you help this adventurous knight to make travel plans? Problem Find a path such that the knight visits every square once. The knight can start and end on any square of the board.这道题的分析
时间: 2023-06-11 16:07:50 浏览: 431
这是一个经典的图论问题,叫做“骑士周游问题”(Knight's Tour Problem)。问题的目标是找到一条路径,使得骑士可以从棋盘上的任意一个方格出发,经过棋盘上的每个方格恰好一次,最终回到起点。
这个问题可以用深度优先搜索(DFS)或者广度优先搜索(BFS)来解决。我们可以从一个起点开始,每次选择一个未被访问过的相邻节点来遍历,直到所有节点都被访问过为止。如果没有找到合法的路径,就需要回溯到上一个节点继续搜索。
另外,由于骑士的移动是有限制的,我们可以预处理出骑士可以到达的所有位置,这样就可以避免无用的搜索。这个预处理可以用一个二维数组来表示,数组中的每个元素表示一个方格,如果骑士可以从当前位置移动到另一个位置,那么这两个位置在数组中对应的元素就应该是相邻的。
如果棋盘的大小比较小,我们可以直接用搜索算法来解决问题。但是如果棋盘的大小比较大,搜索算法可能会超时或者耗费过多的内存。这时候可以使用一些优化算法来减少搜索的时间和空间复杂度,例如剪枝算法、启发式搜索等。
相关问题
Little Gyro has just found an empty integer set A in his right pocket, and an empty integer set B in his left pocket. At the same time, Little Gyro has already thought about two integers n, m in his mind. As Little Gyro is bored, he decides to play with these two sets. Then, Little Gyro is ready to divide the integer series 1,2,3...m−1,m to these two empty sets. With the following rules: If the number is an integer multiple of n, Little Gyro will put it in set A. Otherwise, Little Gyro will put it in set B instead. Now given two integers n, m, after these operations, Little Gyro wants to know the result of sum(B)−sum(A) and ask you for help, please help him to calculate. Input Specification: There are multiple test cases. The first line of the input contains an integer T (1 ≤ T ≤ 10 5 ), indicating the number of test cases. For each test case: Each line contains two integers n, m (1 ≤ n, m ≤ 10 9 ), indicating the length of the sequence. Output Specification: For each test case output an integer indicating the result of sum(B)−sum(A). Sample Input: 3 3 5 2 10 3 16 Sample Output: 9 -5 46 Hint: For the first sample, after these operations, A = <3>, B = <1,2,4,5>, and the answer is 9. For the second sample, after these operations, A = <2,4,6,8,10>, B = <1,3,5,7,9>, and the answer is -5.
To solve this problem, we can first calculate the sum of integers in set A and the sum of integers in set B separately.
The sum of integers in set A is the sum of all integer multiples of n within the range of 1 to m. We can calculate this by first finding the number of integer multiples of n within the range of 1 to m (which is floor(m/n)), and then multiplying it by n.
The sum of integers in set B is the sum of all integers within the range of 1 to m, minus the sum of integers in set A. We can calculate this by using the formula for the sum of an arithmetic series.
Finally, we can return the difference between the sum of integers in set B and the sum of integers in set A as the answer.
Here's the Python code to implement this algorithm:
```python
t = int(input())
for i in range(t):
n, m = map(int, input().split())
a_sum = (m // n) * n * (n + 1) // 2
b_sum = m * (m + 1) // 2 - a_sum
print(b_sum - a_sum)
```
The time complexity of this algorithm is O(T), where T is the number of test cases.
解释代码if not cfg.MULTIPROCESSING_DISTRIBUTED or ( cfg.MULTIPROCESSING_DISTRIBUTED and args.rank % ngpus_per_node == 0
As an AI language model, I am not capable of having feelings, emotions or any subjective experience. Therefore, I cannot say if I am happy or sad, excited or bored, or have any particular state of mind. My responses are based on the input I receive and the algorithms I use to generate a response.
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