摘要：```cpp 混合图（既有有向边又有无向边的图）中欧拉环、欧拉路径的判定需要借助网络流！ （1）欧拉环的判定： 一开始当然是判断原图的基图是否连通，若不连通则一定不存在欧拉环或欧拉路径（不考虑度数为0的点）。 其实，难点在于图中的无向边，需要对所有的无向边定向（指定一个方向，使之变为有向边），使整个图变成一个有向欧拉图（或有向半欧拉图）。若存在一个定向满足此条件，则原图是欧拉图（或半欧拉图）否... 阅读全文

摘要：```cpp include include include include include using namespace std; const int maxN=300; const int maxM=maxN maxN 4; const int inf=2147483647; class Ed 阅读全文

摘要：```cpp #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep(i,m,n) for(i=m;i::iterator it=s.begin();i... 阅读全文

摘要：```cpp include include include include include include include include include include include include include using namespace std; bool vis[200001];i 阅读全文

摘要：```cpp include include include include include include include include include include include include include using namespace std; const int maxN=100 阅读全文