How to do my program more simply? Who khow?
When I send this program - Time limit Exceed on 20 test.
Help, who can!

Program zadacha;
var a:array[1..10000] of integer; b,c,i,j,n:integer; d:array[0..100000] of longint; m:longint;
begin
readln(n);
for i:=1 to n do
 read(a[i]);

readln(m);
for i:=1 to m do begin
 read(b,c);
  for j:=b to c do
   d[i]:=d[i]+a[j];
 end;
for i:=1 to m do
writeln(d[i]);
end.

100.000 * 10.000 = 1.000.000.000
change algoritm (he easy)

So, what algoritm must I use there? Can you tell me?

I don't understand. Please, write once again.

6
4
2
3
1
5
7
2
2 4
3 5 {k,n}

answer:
(4+2+3+1)-(4)=6
(4+2+3+1+5)-(4+2)=9


Clearly: a[n]-a[k-1]

Thank you very much.

that is to amazing

I don't see if it works faster than summing from i to j directly. Summing from 1 to j requires more work and then we yet have to compute another sum and subtract.