Ilya is very fond of graphs, especially trees. During his last trip to the forest Ilya found a very interesting tree rooted at vertex 1. There is an integer number written on each vertex of the tree; the number written on vertex i is equal to ai. Ily…

地址:http://codeforces.com/contest/842/problem/C 题目: C. Ilya And The Tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya is very fond of graphs, especially trees. During his last trip…

[感谢牛老板对D题的指点OTZ] codeforces 842 A. Kirill And The Game[暴力] 给定a的范围[l,r],b的范围[x,y],问是否存在a/b等于k.直接暴力判断即可. #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> using namespace std; typede…

A. Kirill And The Game time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Kirill plays a new computer game. He came to the potion store where he can buy any potion. Each potion is characteriz…

·不论难度,A,C,D自己都有收获! [A. Kirill And The Game] ·全是英文题,述大意:    给出两组区间端点:l,r,x,y和一个k.(都是正整数,保证区间不为空),询问是否在[x,y]区间内存在一个整数p,使得p*k属于[l,r],如果存在,则输出'YES',否则输出'NO'.(1<=l,r,x,y<=107) ·分析:     首先看见了107,发现可以直接O(n)暴力枚举:枚举区间[x,y]的所有数,判断它与k的乘积是否在[l,r]中就可以了.从容AC: #in…

http://codeforces.com/contest/842/problem/C 树 dp 一个数的质因数有限,用set存储,去重 #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <time.h> #include <string> #include <set> #include <map>…

[链接]点击打开链接 [题意] 给你一棵n个点的树,每个点的美丽值定义为根节点到这个点的路径上的所有权值的gcd. 现在,假设对于每一个点,在计算美丽值的时候,你可以将某一个点的权值置为0的话. 问你每个点的最大美丽值可能是多少. [题解] 从根节点开始进行dfs,在往下走的过程中,暴力用set记录下路径中把以上的每一个点删掉后的gcd是什么. 这set里的东西.进行扩展的时候,只能加入不删的点.因为它已经表示删掉一个点的状态了.下面只能都不删 了.然后用另外一个数组now,记录下到根节点到当前…

C. Propagating tree Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/383/problem/C Description Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numb…

D. Happy Tree Party Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/593/problem/D Description Bogdan has a birthday today and mom gave him a tree consisting of n vertecies. For every edge of the tree i, some number xi was w…

D. Water Tree Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/343/problem/D Description Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or…