道路修建 （网络流）

const INF=2000000000;
const maxn=4008;
var r:array[0..maxn] of longint;
    eg:array[0..1000008] of record u,v,w,nt:longint; end;
    el:longint;
    lt:array[0..maxn] of longint;
    h:array[0..maxn] of longint;
    b:array[0..10008] of longint;
    i,j,k,n,s,t,m,x,y:longint;
function op(i,j:longint):longint; inline;
begin
    exit((i-1)*n+j);
end;
function calc(x,y:longint):longint; inline;
begin
    exit(trunc(10*ln(233*(x-y)*(x-y)+1)));
end;
procedure adt(u,v,w:longint);
begin
    inc(el);
    eg[el].u:=u;
    eg[el].v:=v;
    eg[el].w:=w;
    eg[el].nt:=lt[u];
    lt[u]:=el;
end;
procedure add(u,v,w:longint);
begin
     //   writeln(u,' ',v,' ',w);
    adt(u,v,w); adt(v,u,0);
end;
procedure bfs;
var i,l,r,x:longint;
begin
    fillchar(h,sizeof(h),$7f);
    h[t]:=0;
    l:=1; r:=1; b[1]:=t;
    while l<=r do
    begin
        x:=b[l];
        i:=lt[x];
        while i<>0 do
        begin
            if (h[eg[i].v]>=n) and (eg[i xor 1].w>0) then
            begin
                inc(r);
                b[r]:=eg[i].v;
                h[eg[i].v]:=h[x]+1;
            end;
            i:=eg[i].nt;
        end;
        inc(l);
    end;
end;
function min(a,b:longint):longint; inline;
begin
    if a<b then exit(a) else exit(b);
end;
function dfs(u,inl:longint):longint;
var i,v,outl:longint;
begin
    if u=t then exit(inl);
    dfs:=0;
    i:=lt[u];
    while i<>0 do
    begin
        v:=eg[i].v;
        if (eg[i].w>0) and (h[u]=h[v]+1) then
        begin
            outl:=dfs(v,min(eg[i].w,inl));
            dec(inl,outl);
            inc(dfs,outl);
            dec(eg[i].w,outl);
            inc(eg[i xor 1].w,outl);
            if inl=0 then break;
        end;
        i:=eg[i].nt;
    end;
    if inl=0 then h[u]:=-1;
end;
function dinic:longint;
var sum:longint;
begin
    bfs;
    sum:=0;
    while h[s]<n do
    begin
        sum:=sum+dfs(s,INF);
        bfs;
        //writeln(sum);
    end;
    exit(sum);
end;
begin
    //assign(input,'1.in');reset(input);
    el:=1;
    readln(n,m);
    for i:=1 to n do read(r[i]);
    s:=0; t:=n*n+1;
    for i:=1 to n do
    begin
        if i=1 then add(s,op(i,1),calc(0,r[i]))
               else add(s,op(i,1),INF);
        for j:=2 to n do
            if i<>1 then
                add(op(i,j-1),op(i,j),calc(j-1,r[i]))
            else
                add(op(i,j-1),op(i,j),INF);
        if i=1 then add(op(i,n),t,INF) else add(op(i,n),t,calc(n,r[i]))
    end;
 
    for i:=1 to m do
    begin
        readln(x,y);
        for k:=2 to n do
        begin
            add(op(x,k),op(y,k-1),INF);
            add(op(y,k),op(x,k-1),INF);
        end;
    end;
    n:=n*n+1;
    writeln(dinic);
end.