vj p1046 观光旅游 题解

原体叙述

此题简单最小环，用来练练手

最小环如下：

const maxnum=16843009;
var
        n,m,r:longint;
        map,f:array[0..100,0..100]of longint;
procedure main;
var
        i,a,k,j,b,c:longint;
begin
        readln(n,m);
        fillchar(map,sizeof(map),1);
        for i:=1 to m do
                begin
                        readln(a,b,c);
                        map[a,b]:=c;
                        map[b,a]:=c;
                end;
        for i:=1 to n do map[i,i]:=0;
        f:=map;
        r:=maxnum;
        for k:=1 to n do
            begin
                for i:=1 to k-1 do
                    for j:=i+1 to k-1 do
                        if f[i,j]+map[j,k]+map[k,i]<r then
                            r:=f[i,j]+map[j,k]+map[k,i];
                for i:=1 to n do
                    for j:=1 to n do
                        if f[i,j]>f[i,k]+f[k,j] then
                            f[i,j]:=f[i,k]+f[k,j];
            end;
        if r<maxnum then writeln(r) else writeln('No solution.');
end;
begin
       
        while not(eof) do main;
end.