input T 1<=T<=1000 x y output 有多少个起点可以走n(n>=0)步走到(x,y),只能从(x,y)走到(x,y+lcm(x,y))/(x+lcm(x,y),y) 标准解:从(x,y0)走到(x,y),则设x=ag,y0=bg,g=gcd(x,y0),有y=bg+abg=(a+1)bg,因为a,b互质,a,(a+1)互质,所以a和(a+1)b互质,所以若可以从(x,y0)走到(x,y),有gcd(x,y0)=gcd(x,y),然后将x和y中gcd(x,y)除去之

题目链接: L - LCM Walk HDU - 5584 题目大意:首先是T组测试样例,然后给你x和y,这个指的是终点.然后问你有多少个起点能走到这个x和y.每一次走的规则是(m1,m2)到(m1+lcm(m1,m2),m2)或者(m1,m2+lcm(m1,m2)). 具体思路: lcm(m1,m2)=m1*m2/(gcd(m1,m2)).然后m1就能表示成t1*gcd(m1,m2),m2能表示成t2*gcd(m1,m2).然后(m1,m2)就能走到(t1*gcd(m1,m2),t2*gcd(

欢迎参加——BestCoder周年纪念赛(高质量题目+多重奖励) 相遇周期 Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2465    Accepted Submission(s): 1236 Problem Description 2007年3月26日,在中俄两国元首的见证下,中国国家航天局局长孙来燕与俄罗斯联邦航天局局长别尔米诺夫

LCM Walk Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5584 Description A frog has just learned some number theory, and can't wait to show his ability to his girlfriend. Now the frog is sitting on a grid map o

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5584 题意:(x, y)经过一次操作可以变成(x+z, y)或(x, y+z)现在给你个点(ex, ey)输出有多少种可能的起点,这些起点经过若干次操作能变成(ex, ey). 思路:我们考虑其中的一次变换,现在为(x, y)(y > x)那么它显然是由(x, y - z)变换来的.其中z = lcm(x, y - z),lcm(x, y - z) = x*(y-z)/gcd(x, y - z).

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5584 题意: 分析: 这题比赛的时候卡了很久,一直在用数论的方法解决. 其实从终点往前推就可以发现,整个过程中的点的gcd都是一样的,利用这个性质倒着搜索一遍就好了. 相同的gcd均为gcd(6,10) 以(6,10)为例,假设倒数第二个点到达(6−x∗gcd,10),那么x=(6−x∗gcd)∗10/gcd,设6=k1∗gcd, 10=k2∗gcd,那么x满足x=k1∗k2/(k2+1),每次只

Problem Description A frog has just learned some number theory, and can't wait to show his ability to his girlfriend. Now the frog ,,⋯ from the bottom, so are the columns. At first the frog is sitting at grid (sx,sy), and begins his journey. To show

Chinese remainder theorem again Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description 我知道部分同学最近在看中国剩余定理,就这个定理本身,还是比较简单的:假设m1,m2,…,mk两两互素,则下面同余方程组:x≡a1(mod m1)x≡a2(mod m2)…x≡ak(mod mk)在0<=<m1m2…mk内有唯一

最小公倍数 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 69793    Accepted Submission(s): 38394 Problem Description 给定两个正整数,计算这两个数的最小公倍数.   Input 输入包含多组测试数据,每组只有一行,包括两个不大于1000的正整数.   Output 对于每个测试用

A frog has just learned some number theory, and can't wait to show his ability to his girlfriend. Now the frog is sitting on a grid map of infinite rows and columns. Rows are numbered 1,2,⋯from the bottom, so are the columns. At first the frog is sit

#include <cstdio> int gcd(int a,int b) { ) return a; else return gcd(b,a%b); } int main() { int m,n; while (scanf("%d%d",&m,&n)!=EOF) { printf("%d\n",m*n/gcd(m,n)); } ; } 

没用运用好式子...想想其实很简单,首先应该分析,由于每次加一个LCM是大于等于其中任何一个数的,那么我LCM加在哪个数上面,那个数就是会变成大的,这样想,我们就知道,每个(x,y)对应就一种情况. 第二个突破口是,那个式子,我们可以想一想,是不是可以把数进行拆分,我们发现 a=x*k,b=y*k;其中k=gcd(a,b) 并且 x和y互质,这样带入式子,这样我们就把(x*k,y*k)推到了(x*k,x*y+x*y*k),化简即k *(x,(x+1)*y),gcd仍然是k,反过来,我们只需要保证

A frog has just learned some number theory, and can't wait to show his ability to his girlfriend. Now the frog is sitting on a grid map of infinite rows and columns. Rows are numbered 1,2,⋯ from the bottom, so are the columns. At first the frog is si

HDU 1000 A + B Problem  I/O HDU 1001 Sum Problem  数学 HDU 1002 A + B Problem II  高精度加法 HDU 1003 Maxsum  贪心 HDU 1004 Let the Balloon Rise  字典树,map HDU 1005 Number Sequence  求数列循环节 HDU 1007 Quoit Design  最近点对 HDU 1008 Elevator  模拟 HDU 1010 Tempter of th

Problem Description 我知道部分同学最近在看中国剩余定理,就这个定理本身,还是比较简单的: 假设m1,m2,-,mk两两互素,则下面同余方程组: x≡a1(mod m1) x≡a2(mod m2) - x≡ak(mod mk) 在0<=<m1m2-mk内有唯一解. 记Mi=M/mi(1<=i<=k),因为(Mi,mi)=1,故有二个整数pi,qi满足Mipi+miqi=1,如果记ei=Mi/pi,那么会有: ei≡0(mod mj),j!=i ei≡1(mod m

HDU 4627 Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u   Description There are many unsolvable problem in the world.It could be about one or about zero.But this time it is about bigger number. Given an integer n(2 <=

话不多说,日常一水题,水水更健康!┗|｀O′|┛ 嗷~~ a/b + c/d Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 14345    Accepted Submission(s): 7470 Problem Description 给你2个分数,求他们的和,并要求和为最简形式.   Input 输入首先包含一个正整数T(T<=

传送门:http://acm.hdu.edu.cn/showproblem.php?pid=1019 Least Common Multiple Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 61592    Accepted Submission(s): 23486 Problem Description The least comm

题目地址:pid=5407">HDU 5407 题意:CRB有n颗不同的糖果,如今他要吃掉k颗(0<=k<=n),问k取0~n的方案数的最小公倍数是多少. 思路:首先做这道题我们须要必备的几个技能点. 1. LCM(C(n,0), C(n,1),-, C(n,n))=LCM(1,2,3,-n+1)/(n+1).额,这个有一篇证明Kummer定理 2.(1) 乘法逆元定义: 满足a*k≡1 (mod p)的k值就是a关于p的乘法逆元(a,p互质). (2)为什么要用乘法逆元: 当

题意: 输入n,求c(n,0)到c(n,n)的所有组合数的最小公倍数. 输入: 首行输入整数t,表示共有t组测试样例. 每组测试样例包含一个正整数n(1<=n<=1e6). 输出: 输出结果(mod 1e9+7). 感觉蛮变态的,从比赛开始我就是写的这道题,比赛结束还是没写出来…… 期间找到了逆元,最小公倍数,组合数的各种公式,但是爆了一下午tle. 比赛结束,题解告诉我,公式秒杀法…… 但是公式看不懂,幸好有群巨解说,所以有些听懂了,但还是需要继续思考才能弄懂. 题解: 设ans[i]表示i