题目链接:http://codeforces.com/contest/440/problem/D D. Berland Federalization   Recently, Berland faces federalization requests more and more often. The proponents propose to divide the country into separate states. Moreover, they demand that there is a…

[Codeforces 1005F]Berland and the Shortest Paths(最短路树+dfs) 题面 题意:给你一个无向图,1为起点,求生成树让起点到其他个点的距离最小,距离最小的生成树可能有多个.给定k,如果方案数比k小就输出全部方案,否则输出k种方案. 分析 先跑最短路,对于每个点找到它在最短路树上可能的父亲.即对于\((x,y) \in E,dist(y)=dist(x)+len(x,y)\).那么y在最短路上可能的父亲就是x.说"可能"是因为最短路树可能不…

Description Berland National Library has recently been built in the capital of Berland. In addition, in the library you can take any of the collected works of Berland leaders, the library has a reading room. Today was the pilot launch of an automated…

B. Berland National Library time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Berland National Library has recently been built in the capital of Berland. In addition, in the library you can t…

1C - Ancient Berland Circus 思路: 求出三角形外接圆: 然后找出三角形三条边在小数意义下的最大公约数; 然后n=pi*2/fgcd; 求出面积即可: 代码: #include <cmath> #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> using namespace std; #define INF (1e9…

XXI Berland Annual Fair is coming really soon! Traditionally fair consists of nnbooths, arranged in a circle. The booths are numbered 11 through nn clockwise with nnbeing adjacent to 11. The ii-th booths sells some candies for the price of aiai burle…

题目链接:http://codeforces.com/problemset/problem/1296/F 思路: 1————2————3————4————5————6 1->3 2 2->4 3 3->5 3 4->6 5 题目说 (u->v w)途中所有边 e1,e2,e3,...en∈E,满足任意|ex| >= w(ex∈E), 上面图中  3->5 3    4->6 5,说明(|e(4->5)| >= 3 && |e(4-…

这类题一个操作增加多少,一个操作减少多少,求最少刚开始为多少,在中途不会出现负值,模拟一遍,用一个数记下最大的即可 #include<cstdio> #include<cstring> ; ],head[HASH],next[]; void insert(int s) { int h=num[s]%HASH; int u=head[h]; while(u) u=next[u]; next[s]=head[h];//原来的链表头成为s的next head[h]=s;//s成为head…

Problem 给你一棵树,最少删掉哪些边,能使得余下的至少有1个大小刚好为k的残树. 1 ≤ k ≤ n ≤ 400 Solution 用f[i][j]表示以i为根有j个节点的最少删边数量 因为此题要输出删除的边 v[i][j]表示以i为根删掉j个节点需要删去的边对应的(点u,该u点还需要删去的边数量) Notice 因为要输出方案,所以比较复杂 Code #include<cmath> #include<vector> #include<cstdio> #inclu…

题目大意: 给你一棵树,你可以删掉一些边,使得分除去的子树中至少有一棵大小为k. 问最少删去多少边,以及删边的具体方案. 思路: 树形DP. f[i][j]表示以i为根,子树中去掉j个点最少要删边的数量: v[i][j]表示其具体方案. 然后对每个点跑一下背包. 状态转移方程f[x][k+j]=min{f[x][k]+f[y][j]|y为x子结点}. 注意y的不同状态不能同时对x的同一个状态产生影响,所以转移的时候必须把数组复制一遍,将原数组和转移过后的数组隔离开来. v的转移只需要把v[x][…

A - A CodeForces - 1042A There are nn benches in the Berland Central park. It is known that aiai people are currently sitting on the ii-th bench. Another mm people are coming to the park and each of them is going to have a seat on some bench out of n…

第一次就去拉了点思维很神奇的CF题目 2018省赛赛第一次训练 # Origin Title     A CodeForces 607A Chain Reaction     B CodeForces 385C Bear and Prime Numbers     C CodeForces 670D2 Magic Powder - 2     D CodeForces 360B Levko and Array     E CodeForces 68B Energy exchange     F…

B. Berland National LibraryTime Limit: 2 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/567/problem/B Description Berland National Library has recently been built in the capital of Berland. In addition, in the library you can take any of…

B. Ancient Berland Hieroglyphs 题目连接: http://codeforces.com/problemset/problem/164/B Descriptionww.co Polycarpus enjoys studying Berland hieroglyphs. Once Polycarp got hold of two ancient Berland pictures, on each of which was drawn a circle of hierog…

B. Berland National LibraryTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/567/problem/B Description Berland National Library has recently been built in the capital of Berland. In addition, in the library you can take any o…

http://codeforces.com/contest/962/problem/E E. Byteland, Berland and Disputed Cities time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The cities of Byteland and Berland are located on the a…

D. Lakes in Berland 题目连接: http://codeforces.com/contest/723/problem/D Description The map of Berland is a rectangle of the size n × m, which consists of cells of size 1 × 1. Each cell is either land or water. The map is surrounded by the ocean. Lakes…

A. Fashion in Berland 题目连接: http://www.codeforces.com/contest/691/problem/A Description According to rules of the Berland fashion, a jacket should be fastened by all the buttons except only one, but not necessarily it should be the last one. Also if…

C. Old Berland Language 题目连接: http://www.codeforces.com/contest/37/problem/C Description Berland scientists know that the Old Berland language had exactly n words. Those words had lengths of l1, l2, ..., ln letters. Every word consisted of two letter…

E. Berland Local Positioning System Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/534/problem/E Description In Berland a bus travels along the main street of the capital. The street begins from the main square and looks l…

H - Roads not only in Berland Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 25D Description Berland Government decided to improve relations with neighboring countries. First of all, it…

codeforces 808G Anthem of Berland 题面 给定\(s\)串和\(t\)串,字符集是小写字母.\(s\)串中有些位置的值不确定,要求你确定这些位置上的值,使得\(t\)在\(s\)中出现次数最多,输出最多出现次数. 参考博客 http://www.cnblogs.com/Oncle-Ha/p/7061929.html 题解 AC自动机预处理 \(ne[i][j]\):字符串 \(t[i]+j\) 的后缀最长匹配到 \(t[ne[i][j]]\). 状态\(f[i][…

C. Ancient Berland Circus 题目连接: http://www.codeforces.com/contest/1/problem/C Description Nowadays all circuses in Berland have a round arena with diameter 13 meters, but in the past things were different. In Ancient Berland arenas in circuses were s…

题目传送门 /* 题意:给出一系列读者出行的记录,+表示一个读者进入,-表示一个读者离开,可能之前已经有读者在图书馆 构造:now记录当前图书馆人数,sz记录最小的容量,in数组标记进去的读者,分情况讨论一下 */ /************************************************ * Author :Running_Time * Created Time :2015-8-6 0:23:37 * File Name :B.cpp *****************…

海洋包围的小岛,岛内的有湖,'.'代表水,'*'代表陆地,给出的n*m的地图里至少有k个湖,求填掉面积尽量少的水,使得湖的数量正好为k. dfs找出所有水联通块,判断一下是否是湖(海水区非湖).将湖按面积排序,若湖的数量为cnt,填掉前cnt-k个湖. http://codeforces.com/problemset/problem/723/D Examples input 5 4 1*****..*******.*..** output 1*****..*********..** input…

Description The map of Berland is a rectangle of the size n × m, which consists of cells of size 1 × 1. Each cell is either land or water. The map is surrounded by the ocean. Lakes are the maximal regions of water cells, connected by sides, which are…

D. Lakes in Berland time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The map of Berland is a rectangle of the size n × m, which consists of cells of size 1 × 1. Each cell is either land or…

D. Lakes in Berland time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The map of Berland is a rectangle of the size n × m, which consists of cells of size 1 × 1. Each cell is either land or…

A. Parliament of Berland time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output There are n parliamentarians in Berland. They are numbered with integers from 1 to n. It happened that all parliamen…

题目链接: http://codeforces.com/problemset/problem/691/A 题目大意: n个数0或1,要求恰好n-1个1,如果n为1则那个数一定要是1 题目思路: [模拟] 水题一道.看错题目两次.. // //by coolxxx //#include<bits/stdc++.h> #include<iostream> #include<algorithm> #include<string> #include<ioman…