/* http://codeforces.com/problemset/problem/449/C cf 449 C. Jzzhu and Apples 数论+素数+贪心 */ #include <cstdio> #include <algorithm> using namespace std; ; int is_prime[Nmax]; int book[Nmax]; int cnt[Nmax]; int n,ans; void get__prime() { ;i<=n;i…

Codeforces Round #257 (Div. 1) C Codeforces Round #257 (Div. 1) E CF450E C. Jzzhu and Apples time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has picked n apples from his big apple tre…

Jzzhu and Apples 从大的质因子开始贪心, 如果有偶数个则直接组合, 如果是奇数个留下那个质数的两倍, 其余两两组合. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define PLL pair<LL, LL> #define PLI pair<LL, int> #define PII pair&l…

E. Jzzhu and Apples time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has picked n apples from his big apple tree. All the apples are numbered from 1 to n. Now he wants to sell them to…

C. Jzzhu and Apples time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has picked n apples from his big apple tree. All the apples are numbered from 1 to n. Now he wants to sell them to…

E. Jzzhu and Apples time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has picked n apples from his big apple tree. All the apples are numbered from 1 to n. Now he wants to sell them to…

E. Jzzhu and Apples time limit per test: 1 seconds memory limit per test: 256 megabytes input: standard input output: standard output Jzzhu has picked \(n\) apples from his big apple tree. All the apples are numbered from \(1\) to \(n\). Now he wants…

题目链接:http://codeforces.com/problemset/problem/449/C 给你n个数,从1到n.然后从这些数中挑选出不互质的数对最多有多少对. 先是素数筛,显然2的倍数的个数是最多的,所以最后处理.然后处理3,5,7,11...的倍数的数,之前已经挑过的就不能再选了.要是一个素数p的倍数个数是奇数,就把2*p给2 的倍数.这样可以满足p倍数搭配的对数是最优的.最后处理2的倍数就行了. #include <bits/stdc++.h> using namespace…

题意简述 给出正整数n,你要把1-n之间的正整数分成尽可能多组,使得每一组两个数的最大公约数大于1;输出能分成最多组的个数,并按任意顺序输出每组的两个数. 很妙的一道题. 首先我们考虑去处理每个质数的倍数,那么这个质数一定是小于等于 n/2 的,不然它在 n 的范围内是不会有倍数的. 那么我们先把 $1~n/2$ 范围内的所有质数筛出来. 枚举质数 然后我们要怎么用质数去处理答案呢? 首先我们从大到小枚举这些质数,然后去枚举它的倍数. 然鹅这样复杂度不会炸么?不会. $O(\sigma_{i=2…

大意: 求从[1,n]范围选择尽量多的数对, 使得每对数的gcd>1 考虑所有除2以外且不超过n/2的素数p, 若p倍数可以选择的有偶数个, 直接全部划分即可 有奇数个的话, 余下一个2*p不划分, 其余全部划分 最后再将2的倍数全部划分一下即可 #include <iostream> #include <math.h> #include <string.h> #include <algorithm> #include <cstdio> #…

https://vjudge.net/problem/CodeForces-449C 题目大意:1-n编号的苹果两两一对,他们的最大公约数不为1,求这些对的最大匹配. ———————————————————————————————— 我们显然先把素数筛出来. 然后我们从后往前循环素数p,然后p,2p,3p(取过的自动不要)……这些数两两都可以成一对. 但是如果是奇数个,我们就抛掉2p,因为2p一定可以与其他2的倍数一对. 不知道怎么证明…… #include<cstdio> #include&…

嘟嘟嘟 这道题正解是怎么对的其实我也不清楚,总之靠感性理解吧. 首先当然要把1到n / 2的素数都筛出来,因为两两能配对的数一定都是这些素数的倍数.这也就说明对于(n / 2, n]的素数,他们一定不能配对,所以就不用筛他们了. 筛完后我们考虑怎么配对,对于一个素数的所有倍数xi,他们任意两个都可以配对,但是可能配对完后得到的总配对数会减少.因此我们从最大的素数开始两两配对,感性理解就是越大的素数的倍数就越少,因此先尽量满足配对方案少的素数,然后再处理配对方案多的素数. 还有一点,就是当xi的倍…

原题 质因数分解后贪心即可(最后贪2) #include<cstdio> #include<vector> #include<stack> #include<vector> #include<cstring> #define N 100010 using namespace std; bool is[N],mk[N]; int prime[N],num=1,cnt,n,a,b; stack <int> ans; vector <…

A .Jzzhu and Chocolate pro:现在给定一个大小为N*M的巧克力,让你横着或者竖着切K刀,都是切的整数大小,而且不能切在相同的地方,求最大化其中最小的块. (N,M,K<1e9) sol:如果横着切X刀,竖着切Y刀,那么最小的面积=(N/(X+1))*(M/(Y+1)):一看这个公式知道是整数分块了,相同的部分合并. 需要保证X<N,Y<M: #include<bits/stdc++.h> #define ll long long using names…

A - Jzzhu and Children 找到最大的ceil(ai/m)即可 #include <iostream> #include <cmath> using namespace std; int main(){ int n,m; cin >> n >> m; ; ; ; i < n; ++ i){ cin >> a; if(maxv <= ceil(a/m)){ maxv = ceil(a/m); maxIdx = i+;…

codeforces 627 D. Preorder Test 二分 + 树dp 做logn次树dp codeforces 578D.LCS Again 给出一个字符串str,长度n<=10^6,由m种字符组成,问有多少个长度为n,与str的LCS 为 n-1的字符串t 这道题可以用dp套dp,但是我不会阿 可以找规律统计,考虑: 1.取哪个位置 2.放在哪个位置 3.放什么字符 可以知道,如果str分成了block份,每一份的字符相同,则 ans = block * n * (m - 1) 但…

A - Jzzhu and Children Time Limit:1000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Description There are n children in Jzzhu's school. Jzzhu is going to give some candies to them. Let's number all the children from 1 to n. The i-th…

今天老师(orz sansirowaltz)让我们做了很久之前的一场Codeforces Round #257 (Div. 1),这里给出A~C的题解,对应DIV2的C~E. A.Jzzhu and Chocolate time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has a big rectangular cho…

CF449B CF450D http://codeforces.com/contest/450/problem/D http://codeforces.com/contest/449/problem/B Codeforces Round #257 (Div. 2) D Codeforces Round #257 (Div. 1) B D. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megaby…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5303 题意:在一个长为L的环形路径上种着一些苹果树,告诉你苹果树的位置(题目中以0~L指示坐标)及苹果树上的苹果数,现在你要采集所有的苹果(大概是你有一个容量为K的筐,你采集的苹果要装在筐里,采集完要回到坐标0的家里清空筐),问你最少需要走多少路 解:可以想象最多需要走一次整环,剩下的是走两个半环,那么分别对两个半环贪心(由于数据量较小,有很优雅的姿势~) 然后考虑走的这一次整环,由于这次整环的花费…

Pick apples Time Limit: 1000MS Memory limit: 165536K 题目描述 Once ago, there is a mystery yard which only produces three kinds of apples. The number of each kind is infinite. A girl carrying a big bag comes into the yard. She is so surprised because she…

Delicious Apples Problem's Link: http://acm.hdu.edu.cn/showproblem.php?pid=5303 Mean: 一条长为L的环形路上种着n棵苹果数. 第i棵苹果数的位置在xi,有ai个苹果,苹果树的位置按顺时针顺序给出,且都是整数. 在0位置有一个仓库,有一个容量为k的篮子,需要使用这个篮子将所有苹果收到仓库中来,求全过程的最短路. analyse: 首先来分析: 跑整圈的情况只可能出现一次.因为根据贪心的思想,摘完一个单边上最后那颗苹…

Pick apples Time Limit: 1000MS Memory limit: 165536K 题目描述 Once ago, there is a mystery yard which only produces three kinds of apples. The number of each kind is infinite. A girl carrying a big bag comes into the yard. She is so surprised because she…

从客户端(content="<span class="Apple-s...")中检测到有潜在危险的 Request.Form 值. 说明: 请求验证过程检测到有潜在危险的客户端输入值,对请求的处理已经中止.该值可能指示存在危及应用程序安全的尝试,如跨站点脚本攻击.若要允许页面重写应用程序请求验证设置,请将 httpRuntime 配置节中的 requestValidationMode 特性设置为 requestValidationMode="2.0"…

Jzzhu has invented a kind of sequences, they meet the following property: You are given x and y, please calculate fn modulo 1000000007 (109 + 7). Input The first line contains two integers x and y (|x|, |y| ≤ 109). The second line contains a single i…

D. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of A.…

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Alice and Bob decided to eat some fruit. In the kitchen they found a large bag of oranges and apples. Alice immediately took an orange for herself, Bob took an apple. To make the process of sharing the remaining fruit more fun, the friends decided to…

Pick apples Time Limit: 1000MS Memory Limit: 165536KB Submit Statistic Discuss Problem Description Once ago, there is a mystery yard which only produces three kinds of apples. The number of each kind is infinite. A girl carrying a big bag comes into…

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