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  1. //Lib
  2. #include<cstdio>
  3. #include<cstring>
  4. #include<cstdlib>
  5. #include<cmath>
  6. #include<ctime>
  7.  
  8. #include<iostream>
  9. #include<algorithm>
  10. #include<vector>
  11. #include<string>
  12. #include<queue>
  13. #include<stack>
  14. #include<set>
  15. #include<map>
  16. using namespace std;
  17. //Macro
  18. #define rep(i,a,b)  for(int i=a,tt=b;i<=tt;++i)
  19. #define drep(i,a,b) for(int i=a,tt=b;i>=tt;--i)
  20. #define erep(i,e,x) for(int i=x;i;i=e[i].next)
  21. #define irep(i,x)   for(__typeof(x.begin()) i=x.begin();i!=x.end();i++)
  22. #define read()  (strtol(ipos,&ipos,10))
  23. #define sqr(x)  ((x)*(x))
  24. #define pb  push_back
  25. #define PS  system("pause");
  26. typedef long long   ll;
  27. typedef pair<int,int> pii;
  28. const int oo=~0U>>1;
  29. const double inf=1e100;
  30. const double eps=1e-6;
  31. string name="", in=".in", out=".out";
  32. //Var
  33. struct E
  34. {
  35.     int next,node,cap;
  36. }e[100008];
  37. queue<int> q;
  38. int dis[308],h[308];
  39. int n,m,tot=1,st,ed;
  40. void add(int a,int b,int c,int d=0)
  41. {
  42.     e[++tot].next=h[a];e[tot].node=b;e[tot].cap=c;h[a]=tot;
  43.     e[++tot].next=h[b];e[tot].node=a;e[tot].cap=d;h[b]=tot;
  44. }
  45. void Init()
  46. {
  47.     scanf("%d%d",&n,&m);
  48.     int a,b,c;st=n+1;ed=n+2;
  49.     rep(i,1,n)scanf("%d",&c),c?add(st,i,1):add(i,ed,1);
  50.     rep(i,1,m)
  51.     {
  52.         scanf("%d%d",&a,&b);
  53.         add(a,b,1,1);
  54.     }
  55. }
  56. bool BFS()
  57. {
  58.     memset(dis,-1,sizeof dis);
  59.     dis[ed]=0;q.push(ed);
  60.     int u,v,flag=false;
  61.     while(!q.empty())
  62.     {
  63.         u=q.front();q.pop();
  64.         erep(i,e,h[u])
  65.         {
  66.             if(e[i^1].cap&&dis[v=e[i].node]==-1)
  67.             {
  68.                 dis[v]=dis[u]+1;
  69.                 if(v==st)flag=true;
  70.                 q.push(v);
  71.             }
  72.         }
  73.     }
  74.     return flag;
  75. }
  76. int DFS(int u,int low)
  77. {
  78.     if(u==ed)return low;
  79.     int ret=low,tmp,v;
  80.     erep(i,e,h[u])
  81.     {
  82.         if(dis[v=e[i].node]!=dis[u]-1||!e[i].cap)continue;
  83.         tmp=DFS(v,min(low,e[i].cap));
  84.         low-=tmp;
  85.         e[i].cap-=tmp;
  86.         e[i^1].cap+=tmp;
  87.         if(!low)break;
  88.     }
  89.     if(low==ret)dis[u]=-1;
  90.     return ret-low;
  91. }
  92. void Work()
  93. {
  94.     int flow,ans=0;
  95.     while(BFS())
  96.         while(flow=DFS(st,oo))
  97.             ans+=flow;
  98.     cout<<ans<<endl;
  99. }
  100. int main()
  101. {
  102. //  freopen((name+in).c_str(),"r",stdin);
  103. //  freopen((name+out).c_str(),"w",stdout);
  104.     Init();
  105.     Work();
  106.     return 0;
  107. }
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https://ideone.com/RdjQT
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
public

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