2015 ACM-ICPC 沈阳网络赛总结
感觉每次网络赛刚开始总是像打了鸡血一样,斗志满满,不过不出3个小时,斗志就被自己的渣渣实力所消磨了,像前两场比赛一样,这场比赛也是有些困难。
刚开始做了三个水题之后,就是一路卡了。不过呢,队里的大牛还是刷出了第四题,让我印象最深的还是其中的一个数学题了,题目大概是这样的:现在已经在了http://acm.hdu.edu.cn/showproblem.php?pid=5451
Best Solver
Time Limit: 1500/1000 MS (Java/Others) Memory Limit: 65535/102400 K (Java/Others) Total Submission(s): 295 Accepted Submission(s): 129
Problem Description
The so-called best problem solver can easily solve this problem, with his/her childhood sweetheart.
It is known that
y=(5+26√)1+2x
.
For a given integer
x (0≤x<232)
and a given prime number
M (M≤46337)
[y]%M
. (
[y]
means the integer part of
y
)
Input
An integer
T (1 , indicating there are T test cases. Following are T lines, each containing two integers x and M , as introduced above. Output The output contains exactly T lines. Each line contains an integer representing [y]%M . Sample Input 7 0 46337 1 46337 3 46337 1 46337 21 46337 321 46337 4321 46337 Sample Output Case #1: 97 Case #2: 969 Case #3: 16537 Case #4: 969 Case #5: 40453 Case #6: 10211 Case #7: 17947 当时一看惊呆了,2的2的32次方,那不是飞起来了吗,想了很久还是惊呆了。最终还是没做出来。。。。 最后感觉还是差了一题,没拿到现场赛的资格,还是要努力啊! 题解先摆在这,日后补上这题的代码!! 1002.Best solver Degree of Difficulty (0~10):3 Category:Algebra There exists a sequence F(n+2)=a\times F(n+1)+b\times F(n)F(n+2)=a×F(n+1)+b×F(n) such that 5+2\times \sqrt{6}5+2×√6 is an eigenvalue of it. Therefore the problem is converted to compute the power of a 2-order matrix. On the other hand, invertible matrices in Zp form a group of order (p^2- p)(p^2-1)p2−p)(p2−1). Thus we have a period of the power of matrix. The time complexity is O(log^2(n))O(log2(n)).