洛谷水數據，水范圍，給了我們很多可能。暴力貪心，每次選單價最小的，直到完成任務var t,tt,i,m,n,a,b:longint; sum:array[0..10000] of int64;begin readln(n,m); for i:=1 to m do begin readln(a,b); sum[a]:=sum[a]+b; end; for i:=0 to 10000 do begin if sum[i]<>0 then begin t:=t+i*sum[i];tt:=tt+sum[i];end; if tt>=n then break; end; t:=t-(tt-n)*i; writeln(t);end.
