Tyvj P1153 间谍网络

代码来自dxh，注释来自lex

program ty1153;
  2 var
  3    inv,cost,nv,v,f,stk,dfn,low,min,sml:array[1..3000]of longint;
  4    g,ng:array[1..3000,1..3000]of longint;
  5    map:array[1..3000,1..3000]of boolean;
  6    vh,vis:array[1..3000]of boolean;{vh:入栈标志,vis:访问标志}
  7    i,j,k,n,m,top,time,pts,oo,ans1,ans2:longint;
  8 procedure add(a,b:longint);
  9 begin
 10      inc(v[a]);
 11      g[a,v[a]]:=b;
 12 end;
 13 procedure nadd(a,b:longint);    {统计新图各点的出度和入度，并为新图加边}
 14 begin
 15      if map[a,b] then exit;
 16      inc(nv[a]);                {增加a入度}
 17      inc(inv[b]);               {增加b出度}
 18      ng[a,nv[a]]:=b;            {将边加入新图}
 19      map[a,b]:=true;
 20 end;
 21 procedure push(p:longint);
 22 begin
 23      inc(top);
 24      stk[top]:=p;
 25      vh[p]:=true;
 26 end;
 27 function pop:longint;
 28 begin
 29      pop:=stk[top];
 30      vh[stk[top]]:=false;
 31      dec(top);
 32 end;
 33 procedure dfs(p:longint);
 34 var
 35    i,k:longint;
 36 begin
 37      inc(time);
 38      dfn[p]:=time;
 39      low[p]:=dfn[p];
 40      vis[p]:=true;
 41      push(p);
 42      for i:=1 to v[p] do
 43          if not vis[g[p,i]] then
 44             begin
 45                  dfs(g[p,i]);
 46                  if low[g[p,i]]<low[p] then
 47                     low[p]:=low[g[p,i]]
 48             end
 49          else
 50              if vh[g[p,i]] then
 51                 if low[g[p,i]]<low[p] then
 52                    low[p]:=low[g[p,i]];
 53      if low[p]=dfn[p] then
 54         begin
 55              k:=0;
 56              inc(pts);
 57              while k<>p do
 58                    begin
 59                         k:=pop;
 60                         f[k]:=pts;
 61                    end;
 62         end;
 63 end;
 64 procedure merge(p:longint);
 65 var
 66    i:longint;
 67 begin
 68      if cost[p]<min[f[p]] then min[f[p]]:=cost[p];  {该点的最小代价}
 69      if p<sml[f[p]] then sml[f[p]]:=p;              {sml是为了解决不能控制的间谍的最小编号}
 70      for i:=1 to v[p] do                            {缩点建边}
 71               nadd(f[p],f[g[p,i]]);
 72 end;
 73 begin
 74      readln(n);
 75      readln(m);
 76      fillchar(cost,sizeof(cost),$6f);
 77      fillchar(min,sizeof(min),$6f);
 78      for i:=1 to m do
 79          begin
 80               readln(j,k);
 81               cost[j]:=k;
 82          end;
 83      readln(m);
 84      for i:=1 to m do
 85          begin
 86               readln(j,k);
 87               add(j,k);
 88          end;
 89      fillchar(vh,sizeof(vh),false);
 90      fillchar(vis,sizeof(vis),false);
 91      time:=0;
 92      pts:=0;
 93      for i:=1 to n do
 94          if not vis[i] then
 95             dfs(i);
 96      for i:=1 to pts do map[i,i]:=true;        {此分量与自身有路，作用见第15行}
 97      fillchar(sml,sizeof(sml),$6f);
 98      for i:=1 to n do merge(i);
 99      fillchar(oo,sizeof(oo),$6f);
100      ans2:=oo;
101      ans1:=0;
102      for i:=1 to pts do
103          if inv[i]=0 then
104             begin
105                  if min[i]<>oo then            {若该点入度为零，且有间谍可收买，则加钱}
106                     ans1:=ans1+min[i]
107                  else
108                      if sml[i]<ans2 then    　　{若该点无间谍可收买，此分量间谍不可控，更新编号最小之不可控间谍}
109                         ans2:=sml[i];
110             end;
111      if ans2=oo then
112         begin
113              writeln('YES');
114              writeln(ans1);
115         end
116      else
117          begin
118               writeln('NO');
119               writeln(ans2);
120          end;
121 end.