题目连接:http://codeforces.com/contest/688/problem/C 题意:给你一些边,问你能否构成一个二分图 题解:二分图:二分图又称作二部图,是图论中的一种特殊模型. 设G=(V,E)是一个无向图,如果顶点V可分割为两个互不相交的子集(A,B),并且图中的每条边(i,j)所关联的两个顶点i和j分别属于这两个不同的顶点集(i in A,j in B),则称图G为一个二分图. 直接上一个DFS就搞定了 #include<cstdio> #include<set…

E. Mike and Geometry Problem 题目连接: http://www.codeforces.com/contest/689/problem/E Description Mike wants to prepare for IMO but he doesn't know geometry, so his teacher gave him an interesting geometry problem. Let's define f([l, r]) = r - l + 1 to…

D. Friends and Subsequences 题目连接: http://www.codeforces.com/contest/689/problem/D Description Mike and !Mike are old childhood rivals, they are opposite in everything they do, except programming. Today they have a problem they cannot solve on their o…

C. Mike and Chocolate Thieves 题目连接: http://www.codeforces.com/contest/689/problem/C Description Bad news came to Mike's village, some thieves stole a bunch of chocolates from the local factory! Horrible! Aside from loving sweet things, thieves from t…

B. Mike and Shortcuts 题目连接: http://www.codeforces.com/contest/689/problem/B Description Recently, Mike was very busy with studying for exams and contests. Now he is going to chill a bit by doing some sight seeing in the city. City consists of n inter…

A. Mike and Cellphone 题目连接: http://www.codeforces.com/contest/689/problem/A Description While swimming at the beach, Mike has accidentally dropped his cellphone into the water. There was no worry as he bought a cheap replacement phone with an old-fas…

任意门:http://codeforces.com/contest/689/problem/E E. Mike and Geometry Problem time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Mike wants to prepare for IMO but he doesn't know geometry, so…

D - Friends and Subsequences Description Mike and !Mike are old childhood rivals, they are opposite in everything they do, except programming. Today they have a problem they cannot solve on their own, but together (with you) — who knows? Every one of…

C - Mike and Chocolate Thieves Description Bad news came to Mike's village, some thieves stole a bunch of chocolates from the local factory! Horrible! Aside from loving sweet things, thieves from this area are known to be very greedy. So after a thie…

B - Mike and Shortcuts Description Recently, Mike was very busy with studying for exams and contests. Now he is going to chill a bit by doing some sight seeing in the city. City consists of n intersections numbered from 1 to n. Mike starts walking fr…