poj 2383

Description

The galaxy war between the Empire Draco and the Commonwealth of Zibu broke out 3 years ago. Draco established a line of defense called Grot. Grot is a straight line with N defense stations. Because of the cooperation of the stations, Zibu’s Marine Glory cannot march any further but stay outside the line.

A mystery Information Group X benefits form selling information to both sides of the war. Today you the administrator of Zibu’s Intelligence Department got a piece of information about Grot’s defense stations’ arrangement from Information Group X. Your task is to determine whether the information is reliable.

The information consists of M tips. Each tip is either precise or vague.

Precise tip is in the form of P A B X, means defense station A is X light-years north of defense station B.

Vague tip is in the form of V A B, means defense station A is in the north of defense station B, at least 1 light-year, but the precise distance is unknown.

Input

There are several test cases in the input. Each test case starts with two integers N (0 < N ≤ 1000) and M (1 ≤ M ≤ 100000).The next M line each describe a tip, either in precise form or vague form.

Output

Output one line for each test case in the input. Output “Reliable” if It is possible to arrange N defense stations satisfying all the M tips, otherwise output “Unreliable”.

Sample Input

3 4
P 1 2 1
P 2 3 1
V 1 3
P 1 3 1
5 5
V 1 2
V 2 3
V 3 4
V 4 5
V 3 5
Sample Output

Unreliable
Reliable
Source

POJ Monthly–2006.08.27, Dagger

大致题意：给出一些点的精确信息和模糊信息，精确信息给出两点的位置和距离，模糊信息给出两点的位置，但距离大于等于一。试确定是否所有的信息满足条件。

分析：
思路：
由P 可以得到 v - u = w
也就是u - v <= w && v - u <= -w ，
由 V u v 得到 v - u >= 1
也就是 u - v <= -1 ;
建图，使用最短路，判断是否会有负环。

代码：

const
  MaxE=102;
  MaxV=500001;

type
  rec=record
   x,y,w,next:longint;
  end;
var
  n,m,c,qx,i,x,y,w,o,q,p:longint;
  g:array [-1..Maxv] of rec;
  ls:array [-1..Maxe] of longint;
  v,d,list,sum:array [-1..maxe] of longint;
  ch:string;
  boo:boolean;

procedure spfa(first:longint);
var
  head,tail,t,i,qe:longint;
begin
  tail:=1;
  list[1]:=first;
  for i:=1 to n do
  d[i]:=maxlongint;
  d[first]:=0;
  v[first]:=1;
  while tail<>0 do
    begin
      t:=ls[list[tail]];
      qe:=list[tail];
      tail:=tail-1;
      while t>0 do
        with g[t] do
          begin
            if d[x]+w<d[y] then
              begin
                d[y]:=d[x]+w;
                if v[y]=0 then
                  begin
                    v[y]:=1;
                    tail:=tail+1;
                    list[tail]:=y;
                    inc(sum[y]);
                    if (sum[y]>=n) then
                     begin
                      boo:=false;
                      exit;
                     end;
                  end;
              end;
            t:=next;
          end;
      v[qe]:=0;
    end;
end;

procedure add(x,y,w:longint);
 begin
  inc(o);
  g[o].x:=x;
  g[o].y:=y;
  g[o].w:=w;
  g[o].next:=ls[x];
  ls[x]:=o;
 end;

begin
 read(n);
while n>0 do
 begin
  readln(m);
  for i:=1 to m do
   begin
    x:=0; y:=0; w:=0;
    readln(ch);
    p:=pos(' ',ch);
    val(copy(ch,1,p-1),x);
    delete(ch,1,p);
     p:=pos(' ',ch);
    val(copy(ch,1,p-1),y);
    delete(ch,1,p);
    p:=pos(' ',ch);
    val(copy(ch,p+1,length(ch)),w);
    if ch[1]='g' then add(x-1,x+y,-w-1)
                 else add(x+y,x-1,w-1);
   end;
  for i:=0 to n do
  add(-1,i,0);
  boo:=true;
  spfa(-1);
  fillchar(g,sizeof(g),0);
  fillchar(ls,sizeof(ls),0);
  o:=0;
  fillchar(v,sizeof(v),0);
  fillchar(d,sizeof(d),$7f);
  fillchar(sum,sizeof(sum),0);
  fillchar(list,sizeof(list),0);
  if boo then writeln('lamentable kingdom')
         else writeln('successful conspiracy');
  read(n);
 end;
end.