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…

Codeforces Round #297 (Div. 2)C. Ilya and Sticks Time Limit: 2 Sec  Memory Limit: 256 MBSubmit: xxx  Solved: 2xx 题目连接 http://codeforces.com/contest/525/problem/C Description In the evening, after the contest Ilya was bored, and he really felt like ma…

题目传送门 /* 题意:给n个棍子,组成的矩形面积和最大,每根棍子可以-1 贪心:排序后,相邻的进行比较,若可以读入x[p++],然后两两相乘相加就可以了 */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> using namespace std; typedef long long ll; ; const int INF = 0x3f3f3f3f; in…

题目传送门 /* 递推:用cnt记录前缀值,查询区间时,两个区间相减 */ #include <cstdio> #include <algorithm> #include <cmath> #include <cstring> using namespace std; ; const int INF = 0x3f3f3f3f; char s[MAXN]; int cnt[MAXN]; int main(void) //Codeforces Round #186…

[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…

A. Ilya and Diplomas Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/557/problem/A Description Soon a school Olympiad in Informatics will be held in Berland, n schoolchildren will participate there. At a meeting of the jury…

B. Ilya and Queries time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya the Lion wants to help all his friends with passing exams. They need to solve the following problem to pass the IT…

A. Ilya and Bank Account time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya is a very clever lion, he lives in an unusual city ZooVille. In this city all the animals have their rights an…

http://codeforces.com/contest/842/problem/D 树 二进制(路径,每个节点代表一位) #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <time.h> #include <string> #include <set> #include <map> #incl…

D. Ilya and Escalator time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya got tired of sports programming, left university and got a job in the subway. He was given the task to determine…

C. Ilya and Sticks time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output In the evening, after the contest Ilya was bored, and he really felt like maximizing. He remembered that he had a set of …

题目链接:http://codeforces.com/contest/842/problem/D 题意:定义Mex为一个序列中最小的未出现的正整数,给定一个长度为n的序列,然后有m个询问,每个询问给定一个数x,先对序列每个数与x进行异或运算(^),之后输出当前序列修改完之后的Mex. 思路:因为对于原序列和x异或后,得到的新序列再与y异或相当于原序列与z(z=x^y)进行异或,所以问题就可以转化为对于一个数val,原序列和val进行异或后得到新序列的Mex是多少? 考虑01字典树,先把序列的n个…

题目链接:http://codeforces.com/contest/842/problem/B 题意:给定一个圆心在原点(0,0)半径为r的大圆和一个圆内的圆环长度d,然后给你n个小圆,问你有多少个小圆完全位于圆环中 思路:求出每个小圆的圆心和原点的距离dist. 如果满足dist[i]-r[i]>=(r-d)&&dist[i]+r[i]<=r,说明这个小圆完全位于圆环. #define _CRT_SECURE_NO_DEPRECATE #include<iostrea…

题目链接:http://codeforces.com/contest/842/problem/A 题意:给定l,r,x,y,k.问是否存在a (l<=a<=r) 和b (x<=b<=y) 使得 a/b=k (a/b可能为浮点数). 思路:暴力枚举即可. #define _CRT_SECURE_NO_DEPRECATE #include<iostream> #include<cstring> #include<string> #include<…

因为抑或,一眼字典树 但是处理起来比较难 #include<iostream> #include<map> #include<iostream> #include<cstring> #include<cstdio> #include<set> #include<vector> #include<queue> #include<stack> #include<cmath> #include…

D.Vitya and Strange Lesson(字典树) 题意: 给一个长度为\(n\)的非负整数序列,\(m\)次操作,每次先全局异或\(x\),再查询\(mex\) \(1<=n<=3e5\) \(0<=a_i<=3e5\) \(0<=x<=3e5\) 思路:求\(mex\)可以通过按从高位到低位建字典树,判断左子树是否满,若未满,贪心往走,否则往右走,这样查询是\(log\)的 现在就是异或修改,考虑x的第i位,若为1,则以第i-1层结点为根的左右子树都需要…

[比赛链接]click here~~ [题目大意] n个人,获取一到三等文凭,每门文凭有大小范围.求最后文凭各颁发多少 [解题思路]直接枚举了, 看完题,赶紧写了一发代码,发现竟然错过注冊时间.系统提示不能提交代码.真是醉了~~.以后还是得提前注冊: A题,比較简单: 我去,昨天发的代码早上交上去竟然WA了,简直打脸-- 更新一下代码 代码: #include <iostream> #include <bits/stdc++.h> using namespace std; int…

[链接]点击打开链接 [题意] 水题 [题解] 枚举b从x..y看看k*i是不是在l..r之间就好. [错的次数] 0 [反思] 在这了写反思 [代码] #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> #include <map> #include <queue> #include…

[链接]点击打开链接 [题意] 在这里写题意 [题解] 根据圆心到原点的距离这个东西判断一下圆在不在那个环里面就好 [错的次数] 0 [反思] 在这了写反思 [代码] #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> #include <map> #include <queue> #…

[链接]点击打开链接 [题意] 给出一个数组,每次操作将整个数组亦或一个数x,问得到的数组的结果中的mex.mex表示为自然数中第一个没有出现过的数. [题解] 异或的效果是可以累加的,所以不用每次都算出来每一次的a是什么.而只要把前i个询问的x取一下异或和now,然后用异或和对每个ai异或就可以了. 对于这道题.我们需要用字典树来做. 对于一开始的a数组中没有出现的数字,都把它按照位加入到字典树中,最多19位. 设原数组是a,然后没出现的数字组成数组A. 结论:则我们对原数组进行一次异或操作即…

B. Alyona and a tree 题目连接: http://codeforces.com/contest/739/problem/B Description Alyona has a tree with n vertices. The root of the tree is the vertex 1. In each vertex Alyona wrote an positive integer, in the vertex i she wrote ai. Moreover, the g…

题目链接: http://codeforces.com/contest/740/problem/D D. Alyona and a tree time limit per test2 secondsmemory limit per test256 megabytes 问题描述 Alyona has a tree with n vertices. The root of the tree is the vertex 1. In each vertex Alyona wrote an positiv…

题目:http://codeforces.com/contest/1153/problem/D 题意:给你一棵树,每个节点有一个操作,0代表取子节点中最小的那个值,1代表取子节点中最大的值,叶子节点的话就是自己置一个值,有k个子节点,那么每个子节点的值范围 就是1-k,1-k只能用一次 思路:贪心不好取,我肯定是要排列完才知道当前的值是哪个,但是我可以知道当前节点应该是取子节点中排名第几的那个,从而推出根节点1的排名,然后再输出就行,因为是要从 子节点那里递归上来,所以我们采取树形dp #inc…

C. Alyona and the Tree 题目连接: http://www.codeforces.com/contest/682/problem/C Description Alyona decided to go on a diet and went to the forest to get some apples. There she unexpectedly found a magic rooted tree with root in the vertex 1, every verte…

D. Sum in the tree 题目链接:https://codeforces.com/contest/1099/problem/D 题意: 给出一棵树,以及每个点的si,这里的si代表从i号结点到根节点的权值和.但是有些si=-1,这就相当于丢失了当前结点的数据. 假设原本每个点的权值为ai,那么现在求sum{ai}的最小为多少,ai为非负数. 题解: 这题可以单独看每一条链上的s值,假设当前结点为u,儿子结点v,那么就有几种情况: 1.su==-1&&sv==-1,这种不用管,继…

地址:http://codeforces.com/contest/764/problem/C 题目: C. Timofey and a tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Each New Year Timofey and his friends cut down a tree of n vertices…