算法模板——splay区间反转 1
实现的功能：将序列区间反转，并维护
详见BZOJ3223
1 var 2 i,j,k,l,m,n,head,a1,a2:longint; 3 s1:ansistring; 4 a,b,c,d,fat,lef,rig:array[0..200000] of longint; 5 procedure swap(var x,y:longint);inline; 6 var z:longint; 7 begin 8 z:=x;x:=y;y:=z; 9 end; 10 11 procedure ext(x:longint);inline; 12 begin 13 if (x=0) then exit; 14 if c[x]=0 then exit; 15 swap(lef[x],rig[x]); 16 c[x]:=0; 17 c[lef[x]]:=1-c[lef[x]]; 18 c[rig[x]]:=1-c[rig[x]]; 19 c[0]:=0; 20 end; 21 procedure rt(x:longint);inline; 22 var f,l:longint; 23 begin 24 if x=0 then exit; 25 ext(x); 26 if lef[x]=0 then exit; 27 ext(lef[x]); 28 f:=x;l:=lef[x]; 29 b[lef[x]]:=b[x]; 30 b[x]:=b[rig[x]]+1+b[rig[l]]; 31 lef[x]:=rig[l]; 32 fat[rig[l]]:=x; 33 rig[l]:=x; 34 fat[l]:=fat[x]; 35 fat[x]:=l; 36 if rig[fat[l]]=x then rig[fat[l]]:=l; 37 if lef[fat[l]]=x then lef[fat[l]]:=l; 38 fat[0]:=0; 39 end; 40 procedure lt(x:longint);inline; 41 var f,r:longint; 42 begin 43 if x=0 then exit; 44 ext(x);if rig[x]=0 then exit; 45 ext(rig[x]); 46 f:=x;r:=rig[x]; 47 b[rig[x]]:=b[x]; 48 b[x]:=1+b[lef[x]]+b[lef[r]]; 49 rig[x]:=lef[r]; 50 fat[lef[r]]:=x; 51 lef[r]:=x; 52 fat[r]:=fat[x]; 53 fat[x]:=r; 54 if rig[fat[r]]=x then rig[fat[r]]:=r; 55 if lef[fat[r]]=x then lef[fat[r]]:=r; 56 fat[0]:=0; 57 end; 58 procedure ins(x,y:longint);inline; 59 begin 60 if a[y]<a[x] then 61 begin 62 if lef[x]=0 then 63 begin 64 lef[x]:=y; 65 fat[y]:=x; 66 end 67 else ins(lef[x],y); 68 end 69 else 70 begin 71 if rig[x]=0 then 72 begin 73 rig[x]:=y; 74 fat[y]:=x; 75 end 76 else ins(rig[x],y); 77 end; 78 b[x]:=1+b[lef[x]]+b[rig[x]]; 79 end; 80 procedure up2(var x:longint);inline; 81 begin 82 if (fat[x]=0) or (x=0) then exit; 83 if lef[fat[x]]=x then 84 begin 85 if lef[fat[fat[x]]]=fat[x] then 86 begin 87 rt(fat[fat[x]]); 88 rt(fat[x]); 89 end 90 else 91 begin 92 rt(fat[x]); 93 lt(fat[x]); 94 end; 95 end 96 else 97 begin 98 if rig[fat[fat[x]]]=fat[x] then 99 begin 100 lt(fat[fat[x]]); 101 lt(fat[x]); 102 end 103 else 104 begin 105 lt(fat[x]); 106 rt(fat[x]); 107 end; 108 end; 109 end; 110 procedure up1(x:longint);inline; 111 begin 112 if (x=0) or (fat[x]=0) then exit; 113 if lef[fat[x]]=x then rt(fat[x]) else lt(fat[x]); 114 end; 115 procedure splay(x:longint);inline; 116 begin 117 if (x=0) or (fat[x]=0) then exit; 118 while fat[fat[x]]>0 do 119 up2(x); 120 if fat[x]>0 then up2(x); 121 head:=x; 122 end; 123 procedure splay2(x:longint);inline; 124 begin 125 if (x=0) or (fat[x]=0) then exit; 126 while fat[fat[fat[x]]]>0 do 127 up2(x); 128 if fat[fat[x]]>0 then up1(x); 129 end; 130 function getrank(x,y:longint):longint;inline; 131 begin 132 if (x=0) then exit(0); 133 ext(x); 134 if (b[lef[x]]+1)=y then exit(x); 135 if (b[lef[x]]+1)>y then exit(getrank(lef[x],y)) else exit(getrank(rig[x],y-1-b[lef[x]])); 136 end; 137 procedure turn(x,y:longint);inline; 138 var a1,a2:longint; 139 begin 140 if (x=1) and (y=n) then 141 c[head]:=1-c[head] 142 else 143 begin 144 if (x=1) then 145 begin 146 a1:=getrank(head,y+1); 147 splay(a1); 148 ext(a1); 149 c[lef[a1]]:=1-c[lef[a1]]; 150 end 151 else 152 begin 153 if (y=n) then 154 begin 155 a2:=getrank(head,x-1); 156 splay(a2); 157 ext(a2); 158 c[rig[a2]]:=1-c[rig[a2]]; 159 end 160 else 161 begin 162 a1:=getrank(head,x-1); 163 a2:=getrank(head,y+1); 164 splay(a2);splay2(a1); 165 ext(a2);ext(a1); 166 c[rig[a1]]:=1-c[rig[a1]]; 167 end; 168 end; 169 end; 170 end; 171 function showoff(x:longint):ansistring;inline; 172 var s1:ansistring; 173 begin 174 if x=0 then exit(''); 175 ext(x); 176 str(x,s1); 177 exit(showoff(lef[x])+s1+' '+showoff(rig[x])); 178 end; 179 begin 180 readln(n,m); 181 for i:=1 to n do 182 begin 183 a[i]:=i;c[i]:=0;b[i]:=1; 184 end; 185 head:=1; 186 for i:=2 to n do 187 begin 188 ins(head,i); 189 splay(random(i)+1); 190 end; 191 for i:=1 to m do 192 begin 193 readln(a1,a2); 194 turn(a1,a2); 195 end; 196 s1:=showoff(head); 197 writeln(s1); 198 readln; 199 end. 200
