Dertouzos Time Limit: 7000/3500 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1861    Accepted Submission(s): 584 Problem Description A positive proper divisor is a positive divisor of a number n, excluding n its…

感悟:这又是zimpha巨出的一场题,然后04成功fst(也就是这题) 实际上还是too young,要努力增加姿势, 分析:直接枚举这些数不好枚举,换一个角度,枚举x*d,也就是d的另一个乘数是多少 显然  x<=min(d,(n-1)/d),x还得是质数,最后发现x必须小于d的最小因子 然后预处理10w以内的素数,然后每次先得到k=min(d,(n-1)/d),然后看d最小因子是否小于k 这题的关键就在找d的最小因子,我是暴力找的(然后碰上全是大素数就t了) 实际上当d是大素数的时候,k很小…

Dertouzos 题意: 有中文,不说. 题解: 我看了别人的题解,还有个地方没懂, 为什么是 if(d%prime[i]==0) break; ? 代码: #include <bits/stdc++.h> using namespace std; const int INF=0x3f3f3f3f; typedef long long ll; #define PU puts(""); #define PI(A) printf("%d\n",A) #de…

Dertouzos Time Limit: 7000/3500 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 577    Accepted Submission(s): 160 Problem Description A positive proper divisor is a positive divisor of a number n, excluding n itse…

Problem Description A positive proper divisor is a positive divisor of a number n, excluding n itself. For example, 1, 2, and 3 are positive proper divisors of 6, but 6 itself is not.Peter has two positive integers n and d. He would like to know the…

题目给定n和d,都是10的9次方以内,求1到n里面有几个数最大因数是d?1000000组数据.解:求出d的满足p[i]*d<n的最小质因数是第几个质数.即为答案. #include<cstdio> #define N 100002 int t,n,d,pr[N],p[N],num; int main(){ for(int i=2;i<N;i++)if(!pr[i]){ for(int j=i+i;j<N;j+=i) pr[j]=1; p[++num]=i; } scanf(&…

Robot 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5673 Description There is a robot on the origin point of an axis.Every second, the robot can move right one unit length or do nothing.If the robot is on the right of origin point,it can also move…

Triangle 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5914 Description Mr. Frog has n sticks, whose lengths are 1,2, 3⋯n respectively. Wallice is a bad man, so he does not want Mr. Frog to form a triangle with three of the sticks here. He decides…

传送门:http://acm.hdu.edu.cn/showproblem.php?pid=2493 题意:给你一个圆锥,水平放置,圆锥中心轴与地面平行,将圆锥装满水,在圆锥某一表面开一个小洞,流出来水的体积为V,给你地面直径D,高H,让你求小洞里地面的距离.(保证距离大于等于半径,小于等于直径) 题解:因为流出来水的那部分是一个不规则形状(相当于将圆锥水平切开,截面是一个三角形),我们可以二分答案下降高度r,现在关键是求体积. 然后通过一系列很复杂的积分运算,得出结果: 记得最后求出来的答案要…

题目链接 http://acm.hdu.edu.cn/showproblem.php?pid=1568 分析:一道数学题 找出斐波那契数列的通项公式,再利用对数的性质就可得到前几位的数 斐波那契通项公式如下: 取完对数后(记fn为第n个数) log10(fn)=-0.5*log10(5.0)+((double)n)*log(f)/log(10.0)+log10(1-((1-√5)/(1+√5))^n)  其中f=(sqrt(5.0)+1.0)/2.0; 最后取对数的小数部分就可得最终结果 代码如…