程序博客网 > 清华计算机系课程知乎
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YESNO
Data Constraint
var a,b,c:longint; v,r:array[0..10000]of qword; p:boolean; ans:qword;procedure ss(l,u:longint);var i,j:longint; mid:qword;begin i:=l; j:=u; mid:=r[(i+j) div 2]; while i<j do begin while r[i]<mid do inc(i); while r[j]>mid do dec(j); if i<=j then begin v[0]:=v[i]; v[i]:=v[j]; v[j]:=v[0]; r[0]:=r[i]; r[i]:=r[j]; r[j]:=r[0]; inc(i); dec(j); end; end; if j>l then ss(l,j); if i<u then ss(i,u);end;begin while not eof do begin readln(a,b); if (a=0)and(b=0) then exit; for c:=1 to a do begin readln(v[c],r[c]); end; ss(1,a); ans:=b; p:=true; for c:=1 to a do begin if ans>=r[c] then ans:=ans+v[c] else p:=false; end; if p=true then writeln('YES') else writeln('NO'); end;end.