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[bzoj1003] [ZJOI2006]物流运输trans

2013-06-04 20:46 633 查看
不难想到本题的方程为f[i]=min(min(f[j]+cover(j+1,i)*(i-j)+k)(0<j<i),cover(1,i)*i(j=0)),其中cover(x,y)为若第x天到第y天走相同的路的最短路(注意cover(x,y)可能并不存在!!)

之后的就是实现的问题了,由于最近非常不仔细,连一道最裸的完全背包题都因为输入输出调上30+分钟,故代码很挫,各位神犇不要鄙视...

const
MAXM=20;
MAXN=100;
var
l,n,m,k,e,d:longint;
ed,cost,pre:array[1..500]of longint;
last:array[1..MAXM]of longint;
fbd:array[1..MAXN,0..MAXM]of longint;
f:array[0..MAXN]of longint;
dis:Array[1..MAXM]of longint;
h,hash:array[1..MAXM]of boolean;
procedure add(x,y,z:longint);
begin
inc(l);
ed[l]:=y;cost[l]:=z;
pre[l]:=last[x];last[x]:=l;
end;
procedure init;
var i,j,x,y,z:longint;
begin
l:=0;
readln(n,m,k,e);
for i:=1 to e do
begin
readln(x,y,z);
add(x,y,z);
add(y,x,z);
end;
readln(d);
for i:=1 to d do
begin
readln(x,y,z);
for j:=y to z do
begin
inc(fbd[j][0]);
fbd[j][fbd[j][0]]:=x;
end;
end;
end;
function cover(x,y:longint):longint;
var i,j,v,min,top:longint;
begin
fillchar(h,sizeof(h),0);
fillchar(hash,sizeof(hash),0);
top:=m;
for i:=x to y do
for j:=1 to fbd[i][0] do
if(not hash[fbd[i][j]])then
begin
dec(top);hash[fbd[i][j]]:=true;
end;
for i:=1 to m do dis[i]:=maxlongint;
dis[1]:=0;
for i:=1 to top-1 do
begin
min:=maxlongint;v:=-1;
for j:=1 to m do
if(not (hash[j] or h[j]))and(dis[j]<min)then
begin
v:=j;min:=dis[j];
end;
h[v]:=true;
j:=last[v];
while(j>0)do
begin
if(not(hash[ed[j]] or h[ed[j]]))and(dis[ed[j]]>dis[v]+cost[j])then
dis[ed[j]]:=dis[v]+cost[j];
j:=pre[j];
end;
end;
exit(dis[m]);
end;
function min(a,b:longint):longint;
begin
if(a>b)then exit(b) else exit(a);
end;
procedure dp;
var i,j,t:longint;
begin
for i:=1 to n do
begin
f[i]:=cover(1,i);
if(f[i]<>maxlongint)then f[i]:=f[i]*i;
for j:=1 to i-1 do
begin
t:=cover(j+1,i);
if(t<>maxlongint)then
begin
f[i]:=min(f[i],f[j]+t*(i-j)+k);
end;
end;
end;
writeln(f
);
end;
begin
init;
dp;
end.
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