3438: 小M的作物
题目：传送门
题解：
最小割标准水题（做了几天的最小割之后表示是真的水）
为什么水：博主已经做过两道基本一样的题目了...
详情参考：bzoj3894
代码：
1 #include<cstdio> 2 #include<cstring> 3 #include<cstdlib> 4 #include<cmath> 5 #include<algorithm> 6 #define N 510000 7 #define inf 999999999 8 #define qread(x)x=read(); 9 using namespace std; 10 typedef long long LL; 11 inline LL read() 12 { 13 LL f=1,x=0;char ch; 14 while(ch<'0' || ch>'9'){if(ch=='-')f=-1;ch=getchar();} 15 while(ch>='0' && ch<='9'){x=x*10+ch-'0';ch=getchar();} 16 return f*x; 17 } 18 struct node 19 { 20 int x,y,next,other; 21 LL c; 22 }a[N*2];int len,last[N]; 23 LL n,m,st,ed,head,tail; 24 void ins(int x,int y,LL c) 25 { 26 int k1,k2; 27 k1=++len; 28 a[len].x=x;a[len].y=y;a[len].c=c; 29 a[len].next=last[x];last[x]=len; 30 31 k2=++len; 32 a[len].x=y;a[len].y=x;a[len].c=0; 33 a[len].next=last[y];last[y]=len; 34 35 a[k1].other=k2; 36 a[k2].other=k1; 37 } 38 int list[N],h[N]; 39 bool bt_h() 40 { 41 memset(h,0,sizeof(h));h[st]=1; 42 list[1]=st;head=1;tail=2; 43 while(head!=tail) 44 { 45 int x=list[head]; 46 for(int k=last[x];k;k=a[k].next) 47 { 48 int y=a[k].y; 49 if(h[y]==0 && a[k].c>0) 50 { 51 h[y]=h[x]+1; 52 list[tail++]=y; 53 } 54 } 55 head++; 56 } 57 if(h[ed]>0)return true; 58 return false; 59 } 60 int find_flow(int x,LL flow) 61 { 62 if(x==ed)return flow; 63 LL s=0,t; 64 for(int k=last[x];k;k=a[k].next) 65 { 66 int y=a[k].y; 67 if(h[y]==h[x]+1 && a[k].c>0 && s<flow) 68 { 69 s+=t=find_flow(y,min(a[k].c,flow-s)); 70 a[k].c-=t;a[a[k].other].c+=t; 71 } 72 } 73 if(s==0)h[x]=0; 74 return s; 75 } 76 LL A[1100],B[1100],c1[1100],c2[11000]; 77 int main() 78 { 79 len=0;memset(last,0,sizeof(last)); 80 qread(n); 81 LL sum=0; 82 for(int i=1;i<=n;i++){qread(A[i]);sum+=A[i];} 83 for(int i=1;i<=n;i++){qread(B[i]);sum+=B[i];} 84 qread(m);st=N-2;ed=N-1; 85 for(int i=1;i<=n;i++) 86 { 87 ins(st,i,A[i]); 88 ins(i,ed,B[i]); 89 } 90 for(int i=1;i<=m;i++) 91 { 92 int k;qread(k);qread(c1[i]);qread(c2[i]); 93 sum+=c1[i]+c2[i];ins(st,i+n,c1[i]);ins(i+n+m,ed,c2[i]); 94 for(int j=1;j<=k;j++) 95 { 96 int x;qread(x); 97 ins(i+n,x,inf); 98 ins(x,i+n+m,inf); 99 } 100 } 101 LL ans=0; 102 while(bt_h())ans+=find_flow(st,inf); 103 printf("%lld ",sum-ans); 104 return 0; 105 }