delete pics to save space

1.3386.cpp

@@ -0,0 +1,117 @@
+#include<cstdio>
+#include<cstring>
+#include<vector>
+#include<queue>
+#include<algorithm>
+using namespace std;
+const int maxn=2010;
+const int oo=1<<29;
+template<typename T>
+inline void read(T& t)
+{
+    t=0; bool f=false; char ch;
+    while(ch=getchar(),!((ch>='0'&&ch<='9')||ch=='-'));
+    if(ch=='-') f=true,ch=getchar();
+    t=ch-'0';
+    while(ch=getchar(),ch>='0'&&ch<='9') t=t*10+ch-'0';
+    if(f) t=-t;
+}
+template<typename T,typename... Args>
+inline void read(T& t,Args&... args)
+{
+    read(t); read(args...);
+}
+struct Edge
+{
+	int from,to,cap,flow;
+	Edge(int u,int v,int c,int f):from(u),to(v),cap(c),flow(f) { }
+};
+struct Dinic
+{
+	int n,m,s,t;
+	vector<Edge> edges;
+	vector<int> G[maxn];
+	bool vis[maxn];
+	int d[maxn];
+	int cur[maxn];
+	inline void AddEdge(int from,int to,int cap)
+	{
+		edges.push_back((Edge){from,to,cap,0});
+		edges.push_back((Edge){to,from,0,0});
+		m=edges.size();
+		G[from].push_back(m-2);
+		G[to].push_back(m-1);
+	}
+	inline bool BFS()
+	{
+		memset(vis,0,sizeof(vis));
+		queue<int> Q;
+		Q.push(s); d[s]=0; vis[s]=true;
+		while(Q.size())
+		{
+			int u=Q.front(); Q.pop();
+			for(int i=0;i<G[u].size();i++)
+			{
+				Edge &e=edges[G[u][i]];
+				if(!vis[e.to]&&e.cap>e.flow)
+				{
+					vis[e.to]=true;
+					d[e.to]=d[u]+1;
+					Q.push(e.to);
+				}
+			}
+		}
+		return vis[t];
+	}
+	int DFS(int u,int a)
+	{
+		if(u==t||a==0) return a;
+		int flow=0,f;
+		for(int &i=cur[u];i<G[u].size();i++)
+		{
+			Edge &e=edges[G[u][i]];
+			if(d[u]+1==d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>0)
+			{
+				e.flow+=f; flow+=f;
+				edges[G[u][i]^1].flow-=f; a-=f;
+				if(a==0) break;
+			}
+		}
+		return flow;
+	}
+	int Maxflow(int s,int t)
+	{
+		this->s=s; this->t=t;
+		int flow=0;
+		while(BFS())
+		{
+			memset(cur,0,sizeof(cur));
+			flow+=DFS(s,oo);
+		}
+		return flow;
+	}
+}MainAgo;
+int n,m,e,u,v,s,t;
+int color[maxn];
+void dfs(int o,int c)
+{
+	if(color[o]) return;
+	color[o]=c;
+	int sz=MainAgo.G[o].size();
+	for(int i=0;i<sz;i++) dfs(MainAgo.edges[i].to,3-c);
+}
+int main()
+{
+	read(n,m,e);
+	for(int i=0;i<e;i++)
+	{
+		read(u,v);
+		if(v>m) continue;
+		MainAgo.AddEdge(u,n+v,1);
+	}
+	s=n+m+1; t=n+m+2;
+	for(int i=1;i<=n;i++) MainAgo.AddEdge(s,i,1);
+	for(int i=1;i<=m;i++) MainAgo.AddEdge(i+n,t,1);
+	printf("%d\n",MainAgo.Maxflow(s,t));
+	return 0;
+}