Annual Congress of MUD（最大流）

  1 #include <bits/stdc++.h>
  2 using namespace std;
  3 const int MAXN=305;
  4 const int INF=1e9+7;
  5 struct Max_flow
  6 {
  7     struct
  8     {
  9         int v,cap,next;
 10     } e[MAXN*MAXN];
 11     int cnt_edge,cur_clk,head[MAXN];
 12     void init(int cnt)
 13     {
 14         cnt_edge=0;
 15         memset(head,0xff,sizeof(int)*cnt);
 16     }
 17     int add_edge_(int u,int v,int cap)
 18     {
 19         e[cnt_edge]={v,cap,head[u]};
 20         head[u]=cnt_edge;
 21         return cnt_edge++;
 22     }
 23     int add_edge(int u,int v,int cap)
 24     {
 25         int res=add_edge_(u,v,cap);
 26         add_edge_(v,u,0);
 27         return res;
 28     }
 29     int clk[MAXN],pre[MAXN];
 30     queue<int> que;
 31     bool bfs(int s,int t)
 32     {
 33         while(!que.empty()) que.pop();
 34         cur_clk++;
 35         clk[s]=cur_clk;
 36         que.push(s);
 37         while(!que.empty())
 38         {
 39             int u=que.front();
 40             que.pop();
 41             for(int i=head[u]; i!=-1; i=e[i].next)
 42             {
 43                 if(e[i].cap>0)
 44                 {
 45                     int v=e[i].v;
 46                     if(clk[v]!=cur_clk)
 47                     {
 48                         pre[v]=i;
 49                         clk[v]=cur_clk;
 50                         if(v==t) return true;
 51                         que.push(v);
 52                     }
 53                 }
 54             }
 55         }
 56         return false;
 57     }
 58     int max_flow(int s,int t)
 59     {
 60         int flow=0;
 61         while(bfs(s,t))
 62         {
 63             int min_cap=INF;
 64             for(int u=t;u!=s;u=e[pre[u]^1].v)
 65             {
 66                 if(min_cap>e[pre[u]].cap) min_cap=e[pre[u]].cap;
 67             }
 68             for(int u=t; u!=s; u=e[pre[u]^1].v)
 69             {
 70                 e[pre[u]].cap-=min_cap;
 71                 e[pre[u]^1].cap+=min_cap;
 72             }
 73             flow+=min_cap;
 74         }
 75         return flow;
 76     }
 77 } G;
 78 int vis[30][30],idx[30][30],edg_t[30],s_edg[MAXN];
 79 int n,d,now,m,s,t,flow;
 80 bool flag;
 81 int main()
 82 {
 83     while(scanf("%d",&n)!=EOF && n)
 84     {
 85         now++,m=0,flow=0,flag=false;
 86         scanf("%d",&d);
 87         for(int i=0;i<d;i++)
 88         {
 89             for(int j=i;j<d;j++)
 90             {
 91                 idx[i][j]=m++;
 92             }
 93         }
 94         G.init(m+d+2);
 95         s=m+d,t=m+d+1;
 96         for(int i=0;i<d;i++) edg_t[i]=G.add_edge(m+i,t,0);
 97         for(int i=0;i<n;i++)
 98         {
 99             int x,y;
100             scanf("%d %d",&x,&y);
101             x--,y--;
102             int v=idx[x][y];
103             if(vis[x][y]!=now)
104             {
105                 vis[x][y]=now;
106                 for(int i=x;i<=y;i++) G.add_edge(v,m+i,INF);
107                 s_edg[v]=G.add_edge(s,v,1);
108             }
109             else
110             {
111                 G.e[s_edg[v]].cap++;
112             }
113             flow+=G.max_flow(s,t);
114             //cout<<"ni"<<"->"<<flow<<endl;
115             if(flow!=i+1)
116             {
117                 if(flag) printf(" ");
118                 else flag=true;
119                 printf("%d",i+1);
120                 for(int i=0;i<d;i++) G.e[edg_t[i]].cap++;
121             }
122         }
123         puts("");
124     }
125     return 0;
126 }