题意:给定一个图,问你只能向上向下,或者平着走,有多少种方法可以走到最后一个格. 析:首先先考虑,如果没有平的情况就是calelan数了,现在有平的情况,那么就枚举呗,因为数很大,所以要用高精度. 答案应该是sum(C(n, 2*i)*C(n, i)/(i+1)) = a1 + a2 + a3 + ....,然后可以再化简一下,成为一个递推式ai = ai-1 * (n-2*i+1)*(n-2*i+2)/(k*(k+1)): 这次用记事本写的,然后没有测试,直接交的,虽然CE了一发,但还是挺好的…

option=com_onlinejudge&Itemid=8&category=471&page=show_problem&problem=4224" style="">题目链接:uva 1478 - Delta Wave 题目大意:对于每一个位置来说,能够向上,水平,向下.坐标不能位负.每次上下移动最多为1. 给定n问说有多少种不同的图.结果对10100取模. 解题思路:由于最后都要落回y=0的位置,所以上升的次数和下降的次数是同样的…

题目链接:https://vjudge.net/problem/HDU-3723 Delta Wave Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1468    Accepted Submission(s): 483 Problem Description A delta wave is a high amplitude brain…

Sequence II Time Limit: 9000/4500 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 849    Accepted Submission(s): 204 Problem Description Mr. Frog has an integer sequence of length n, which can be denoted as a1,a2,⋯…

hdu 1568 (log取对数 / Fib数通项公式) 2007年到来了.经过2006年一年的修炼,数学神童zouyu终于把0到100000000的Fibonacci数列 (f[0]=0,f[1]=1;f[i] = f[i-1]+f[i-2](i>=2))的值全部给背了下来. 接下来,CodeStar决定要考考他,于是每问他一个数字,他就要把答案说出来,不过有的数字太长了.所以规定超过4位的只要说出前4位就可以了,可是CodeStar自己又记不住.于是他决定编写一个程序来测验zouyu说的是否…

Train Problem II Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %I64d & %I64u Submit Status Description As we all know the Train Problem I, the boss of the Ignatius Train Station want to know if all the trains come in strict-increasing…

Problem Description Oneof the first users of BIT's new supercomputer was Chip Diller. He extended hisexploration of powers of 3 to go from 0 to 333 and he explored taking varioussums of those numbers.  ``This supercomputer is great,'' remarked Chip.…

Geometric Progression Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://bestcoder.hdu.edu.cn/contests/contest_chineseproblem.php?cid=628&pid=1001 Description 判断一个数列是否为等比数列. 在数学中,等比数列,是一个数列,这个数列中的第一项之后的每一项是前一项乘上一个固定的非零实数(我们称之为公比).比如,数列 2, 6, 18, 54,…

题目链接 题意:给定一个很大的数,把他们分为数个回文数的和,分的个数不超过50个,输出个数并输出每个数,special judge. 题解:现场赛的时候很快想出来了思路,把这个数从中间分为两部分,当位数为偶数的时候3456就分为34和56,34-1=33,回文数3333,3456-3333=123然后继续算:当位数为奇数的时候34567就分为34和67,5-1=4,回文数34443,34567-34443=124然后继续算.但是一年都没有写过高精度减法的题了,这个大模拟写了很久最后判断奇偶性都判…

How many Fibs? Description Recall the definition of the Fibonacci numbers: f1 := 1 f2 := 2 fn := f n-1 + f n-2 (n>=3) Given two numbers a and b, calculate how many Fibonacci numbers are in the range [a,b]. Input The input contains several test cases.…