PKU 1149 - PIGS

PKU/1149 - PIGS.cpp

@@ -0,0 +1,117 @@
+#include <cstdio>
+#include <climits>
+#include <algorithm>
+
+using namespace std;
+
+struct flow_graph{
+    int MAX_V,E,s,t,head,tail;
+    int *cap,*to,*next,*last,*dist,*q,*now;
+
+    flow_graph(){}
+
+    flow_graph(int V, int MAX_E){
+        MAX_V = V; E = 0;
+        cap = new int[2*MAX_E], to = new int[2*MAX_E], next = new int[2*MAX_E];
+        last = new int[MAX_V], q = new int[MAX_V];
+        dist = new int[MAX_V], now = new int[MAX_V];
+        fill(last,last+MAX_V,-1);
+    }
+
+    void add_edge(int u, int v, int uv, int vu = 0){
+        to[E] = v, cap[E] = uv, next[E] = last[u]; last[u] = E++;
+        to[E] = u, cap[E] = vu, next[E] = last[v]; last[v] = E++;
+    }
+
+    bool bfs(){
+        fill(dist,dist+MAX_V,-1);
+        head = tail = 0;
+
+        q[tail] = t; ++tail;
+        dist[t] = 0;
+
+        while(head<tail){
+            int v = q[head]; ++head;
+
+            for(int e = last[v];e!=-1;e = next[e]){
+                if(cap[e^1]>0 && dist[to[e]]==-1){
+                    q[tail] = to[e]; ++tail;
+                    dist[to[e]] = dist[v]+1;
+                }
+            }
+        }
+
+        return dist[s]!=-1;
+    }
+
+    int dfs(int v, int f){
+        if(v==t) return f;
+
+        for(int &e = now[v];e!=-1;e = next[e]){
+            if(cap[e]>0 && dist[to[e]]==dist[v]-1){
+                int ret = dfs(to[e],min(f,cap[e]));
+
+                if(ret>0){
+                    cap[e] -= ret;
+                    cap[e^1] += ret;
+                    return ret;
+                }
+            }
+        }
+
+        return 0;
+    }
+
+    int max_flow(int source, int sink){
+        s = source; t = sink;
+        int f = 0,x;
+
+        while(bfs()){
+            for(int i = 0;i<MAX_V;++i) now[i] = last[i];
+
+            while(true){
+                x = dfs(s,INT_MAX);
+                if(x==0) break;
+                f += x;
+            }
+        }
+
+        return f;
+    }
+}G(102,2*100+1000*100);
+
+int main(){
+	int M,N;
+	scanf("%d %d",&M,&N);
+
+	int cap[M];
+	for(int i = 0;i<M;++i) scanf("%d",&cap[i]);
+
+	int A,B,K,first[M];
+	fill(first,first+M,0);
+
+	for(int i = 1;i<=N;++i){
+		scanf("%d",&A);
+		int sum = 0;
+
+		for(int j = 0;j<A;++j){
+			scanf("%d",&K);
+			--K;
+
+			if(first[K]==0){
+				sum += cap[K];
+				first[K] = i;
+			}else{
+				G.add_edge(first[K],i,INT_MAX);
+			}
+		}
+
+		G.add_edge(0,i,sum);
+		scanf("%d",&B);
+		G.add_edge(i,1+N,B);
+	}
+
+	printf("%d\n",G.max_flow(0,1+N));
+
+	return 0;
+}