分析：f1[i,j]表示（i，j）左上角数字和，f[i,j]=f[i-1,j]+f[i,j-1]-f[i-1,j-1],+f[i,j]，右下角数字和同理。
代码
const
maxn=1500;
var
f1,f2,a:array[-maxn..maxn,-maxn..maxn] of longint;
n,t,x,y,i,j:longint;
begin
assign(input,’scout.in’);reset(input);
assign(output,’scout.out’);rewrite(output);
readln(n,t);
for i:=1 to n do
for j:=1 to n do
read(a[i,j]);
for i:=1 to n do
for j:=1 to n do
f1[i,j]:=f1[i,j-1]+f1[i-1,j]-f1[i-1,j-1]+a[i-1,j-1];
for i:=n downto 1 do
for j:=n downto 1 do
f2[i,j]:=f2[i,j+1]+f2[i+1,j]-f2[i+1,j+1]+a[i+1,j+1];
for i:=1 to t do
begin
readln(x,y);
writeln(f1[x,y]+f2[x,y]);
end;
close(input);close(output);
end.