A. Ring road time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Nowadays the one-way traffic is introduced all over the world in order to improve driving safety and reduce traffic jams. The g…

    题意             n个数1~n按顺序围成一个圈...现在在某些两点间加边..边可以加在圈内或者圈外..问是否会发生冲突?如果不发生冲突..输每一条边是放圈内还是圈外.     题解             这道题和POJ 3207差不多了..只是那道题只要判断是否存在不要输出方案...发现个很严重的问题..POJ 3207的数据实在是太弱了..我上一个程序里判断两个线段是否相交是个错了..都让我AC了..导致我做这题是沿用了思路...浪费了很多时间...          …

HDOJ(HDU).1016 Prime Ring Problem (DFS) [从零开始DFS(3)] 从零开始DFS HDOJ.1342 Lotto [从零开始DFS(0)] - DFS思想与框架/双重DFS HDOJ.1010 Tempter of the Bone [从零开始DFS(1)] -DFS四向搜索/奇偶剪枝 HDOJ(HDU).1015 Safecracker [从零开始DFS(2)] -DFS四向搜索变种 HDOJ(HDU).1016 Prime Ring Problem (…

[Codeforces 1214D]Treasure Island(dfs) 题面 给出一个n*m的字符矩阵,'.'表示能通过,'#'表示不能通过.每步可以往下或往右走.问至少把多少个'.'变成'#',才能让从(1,1)出发不能到达(n,m) \(n \times m \leq 10^6\) 分析 第一眼还以为是最小割,一看数据范围感觉会TLE.实际上搜索就可以了. 首先发现答案肯定是0,1,2中的一个(输出rand()%3),因为最多用2个'#',把(1,1)右侧和下方堵住就可以了. 然后注意…

[Codeforces 163D]Large Refrigerator (DFS+剪枝) 题面 已知一个长方体的体积为V,三边长a,b,c均为正整数,求长方体的最小表面积S V以质因数分解的形式给出 分析 暴力做法很容易想到,按照质因子的指数枚举a,b,然后就能直接算出c,然后就可以得到表面积S=2(ab+bc+ac) 考虑优化: 1.搜索顺序:保证\(a \geq b \geq c\),枚举质因数时从大到小枚举a,从小到大枚举b 2.可行性剪枝:枚举a的时候保证\(a^3 \leq V\),枚…

C. Journey time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output There are n cities and n - 1 roads in the Seven Kingdoms, each road connects two cities and we can reach any city from any other…

http://codeforces.com/contest/738/problem/C Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's…

Evil Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100463/attachments Description Richard is evil. He wants to give another geometry problem to the participants of this contest and I’m afraid I have no choice but to comply. W…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 31031    Accepted Submission(s): 13755 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

题目网址:http://codeforces.com/contest/825/problem/B 题目:   Alice and Bob play 5-in-a-row game. They have a playing field of size 10 × 10. In turns they put either crosses or noughts, one at a time. Alice puts crosses and Bob puts noughts. In current matc…