P1699: [Usaco2007 Jan]Balanced Lineup排队

很明显是一道RMQ问题，倍增法，维护一下区域的最大/小值就行了。

 var n,i,j,q,f,t,times:longint;
 hmin,hmax:array[..,..] of longint;
 function min(a,b:longint):longint;
 begin
   if a>b then exit(b)
     else exit(a);
 end;
 function max(a,b:longint):longint;
 begin
   if a>b then exit(a)
     else exit(b);
 end;
 begin
   readln(n,q);
   for i:= to n do
     begin
       readln(hmax[,i]);
       hmin[,i]:=hmax[,i];
     end;
   for i:= to trunc(ln(n)/ln())+ do
     for j:= to n-( shl i)+ do
       begin
         hmin[i,j]:=min(hmin[i-,j],hmin[i-,j+( shl (i-))]);
         hmax[i,j]:=max(hmax[i-,j],hmax[i-,j+( shl (i-))]);
       end;
   for i:= to q do
     begin
       readln(f,t);
       times:=trunc(ln(t-f+)/ln());
       writeln(max(hmax[times,f],hmax[times,t-( shl times)+])-
               min(hmin[times,f],hmin[times,t-( shl times)+]));
     end;
 end.

(转载请注明出处：http://www.cnblogs.com/Kalenda/)