题意：见题面
思路：因为每个时刻要么全是人要么全是宠物，所以可以一棵splay解决
维护单点插入，单点删除，求前驱，求后继即可
1 var t:array[0..100000,0..1]of longint; 2 num,fa:array[0..100000]of longint; 3 n,cnt,t1,t2,i,root,p,x,y:longint; 4 ans:int64; 5 6 procedure rotate(x:longint;var k:longint); 7 var y,z,l,r:longint; 8 begin 9 y:=fa[x]; z:=fa[y]; 10 if t[y,0]=x then l:=0 11 else l:=1; 12 r:=1-l; 13 if y=k then k:=x 14 else 15 if t[z,0]=y then t[z,0]:=x 16 else t[z,1]:=x; 17 fa[x]:=z; fa[y]:=x; fa[t[x,r]]:=y; 18 t[y,l]:=t[x,r]; t[x,r]:=y; 19 end; 20 21 procedure splay(x:longint;var k:longint); 22 var y,z:longint; 23 begin 24 while x<>k do 25 begin 26 y:=fa[x]; z:=fa[y]; 27 if y<>k then 28 begin 29 if (t[y,0]=x)xor(t[z,0]=y) then rotate(x,k) 30 else rotate(y,k); 31 end; 32 rotate(x,k); 33 end; 34 end; 35 36 procedure ins(var k:longint;x,last:longint); 37 begin 38 if k=0 then 39 begin 40 inc(cnt); 41 k:=cnt; num[k]:=x; 42 fa[k]:=last; splay(k,root); 43 exit; 44 end; 45 if x<num[k] then ins(t[k,0],x,k) 46 else ins(t[k,1],x,k); 47 end; 48 49 procedure del(x:longint); 50 var k:longint; 51 begin 52 splay(x,root); 53 if t[x,0]*t[x,1]=0 then root:=t[x,0]+t[x,1] 54 else 55 begin 56 k:=t[x,1]; 57 while t[k,0]>0 do k:=t[k,0]; 58 t[k,0]:=t[x,0]; fa[t[x,0]]:=k; 59 root:=t[x,1]; 60 end; 61 fa[root]:=0; 62 end; 63 64 procedure pred(k,x:longint); 65 begin 66 if k=0 then exit; 67 if num[k]<=x then 68 begin 69 t1:=k; pred(t[k,1],x); 70 end 71 else pred(t[k,0],x); 72 end; 73 74 procedure succ(k,x:longint); 75 begin 76 if k=0 then exit; 77 if num[k]>=x then 78 begin 79 t2:=k; succ(t[k,0],x); 80 end 81 else succ(t[k,1],x); 82 end; 83 84 begin 85 assign(input,'bzoj1208.in'); reset(input); 86 assign(output,'bzoj1208.out'); rewrite(output); 87 readln(n); 88 for i:=1 to n do 89 begin 90 readln(x,y); 91 if root=0 then begin p:=x; ins(root,y,0); end 92 else if p=x then ins(root,y,0) 93 else 94 begin 95 t1:=-1; t2:=-1; 96 pred(root,y); succ(root,y); 97 if t1=-1 then 98 begin 99 ans:=ans+num[t2]-y; ans:=ans mod 1000000; del(t2); 100 end 101 else if t2=-1 then 102 begin 103 ans:=ans+y-num[t1]; ans:=ans mod 1000000; del(t1); 104 end 105 else 106 if y-num[t1]>num[t2]-y then 107 begin 108 ans:=ans+num[t2]-y; ans:=ans mod 1000000; del(t2); 109 end 110 else 111 begin 112 ans:=ans+y-num[t1]; ans:=ans mod 1000000; del(t1); 113 end; 114 end; 115 end; 116 writeln(ans); 117 close(input); 118 close(output); 119 end.