树链剖分在边上的应用
比维护点稍微麻烦一点，是对每条边标号，并且要记录每个点父亲边的编号和重儿子
然后注意各种细节
线段树上和bzoj1858的维护方法类似，覆盖的优先级高于加
具体见程序，完全是为了提升状态的练习
1 type node=record 2 po,next,num:longint; 3 end; 4 5 var son,a,d,fa,fp,f2,b,c,p,size,top:array[0..100010] of longint; 6 w:array[0..200010] of node; 7 tree,laz1,laz2:array[0..100010*4] of longint; 8 x,y,z,i,n,t:longint; 9 ch:char; 10 s:string; 11 12 function max(a,b:longint):longint; 13 begin 14 if a>b then exit(a) else exit(b); 15 end; 16 17 procedure add(x,y,c:longint); 18 begin 19 inc(t); 20 w[t].po:=y; 21 w[t].num:=c; 22 w[t].next:=p[x]; 23 p[x]:=t; 24 end; 25 26 procedure swap(var a,b:longint); 27 var c:longint; 28 begin 29 c:=a; 30 a:=b; 31 b:=c; 32 end; 33 34 procedure push(i:longint); 35 begin 36 if laz1[i]<>-1 then 37 begin 38 tree[i*2]:=laz1[i]; 39 tree[i*2+1]:=laz1[i]; 40 laz1[i*2]:=laz1[i]; 41 laz1[i*2+1]:=laz1[i]; 42 laz1[i]:=-1; 43 laz2[i]:=0; 44 end; 45 if laz2[i]<>0 then 46 begin 47 inc(tree[i*2],laz2[i]); 48 inc(tree[i*2+1],laz2[i]); 49 if laz1[i*2]<>-1 then inc(laz1[i*2],laz2[i]) 50 else inc(laz2[i*2],laz2[i]); 51 if laz1[i*2+1]<>-1 then inc(laz1[i*2+1],laz2[i]) 52 else inc(laz2[i*2+1],laz2[i]); 53 laz2[i]:=0; 54 end; 55 end; 56 57 procedure dfs1(x:longint); 58 var i,y:longint; 59 begin 60 i:=p[x]; 61 size[x]:=1; 62 while i<>0 do 63 begin 64 y:=w[i].po; 65 if fa[x]<>y then 66 begin 67 fp[y]:=w[i].num; 68 fa[y]:=x; 69 d[y]:=d[x]+1; 70 dfs1(y); 71 size[x]:=size[x]+size[y]; 72 end; 73 i:=w[i].next; 74 end; 75 end; 76 77 procedure dfs2(x:longint); 78 var i,y,q:longint; 79 begin 80 i:=p[x]; 81 q:=0; 82 while i<>0 do 83 begin 84 if fa[w[i].po]=x then 85 if size[w[q].po]<size[w[i].po] then q:=i; 86 i:=w[i].next; 87 end; 88 if q=0 then exit; 89 top[w[q].po]:=top[x]; 90 son[x]:=w[q].num; 91 inc(t); 92 c[t]:=w[q].num; 93 b[w[q].num]:=t; 94 dfs2(w[q].po); 95 i:=p[x]; 96 while i<>0 do 97 begin 98 y:=w[i].po; 99 if (i<>q) and (fa[y]=x) then 100 begin 101 inc(t); 102 c[t]:=w[i].num; 103 b[w[i].num]:=t; 104 top[y]:=y; 105 dfs2(y); 106 end; 107 i:=w[i].next; 108 end; 109 end; 110 111 procedure build(i,l,r:longint); 112 var m:longint; 113 begin 114 laz1[i]:=-1; 115 laz2[i]:=0; 116 if l=r then tree[i]:=a[c[l]] 117 else begin 118 m:=(l+r) shr 1; 119 build(i*2,l,m); 120 build(i*2+1,m+1,r); 121 tree[i]:=max(tree[i*2],tree[i*2+1]); 122 end; 123 end; 124 125 procedure change(i,l,r,x,y,z:longint); 126 var m:longint; 127 begin 128 if x>y then exit; 129 if (x<=l) and (y>=r) then 130 begin 131 laz1[i]:=z; 132 tree[i]:=z; 133 laz2[i]:=0; 134 end 135 else begin 136 push(i); 137 m:=(l+r) shr 1; 138 if x<=m then change(i*2,l,m,x,y,z); 139 if y>m then change(i*2+1,m+1,r,x,y,z); 140 tree[i]:=max(tree[i*2],tree[i*2+1]); 141 end; 142 end; 143 144 procedure fadd(i,l,r,x,y:longint); 145 var m:longint; 146 begin 147 if x>y then exit; 148 if (x<=l) and (y>=r) then 149 begin 150 if laz1[i]<>-1 then inc(laz1[i],z) 151 else inc(laz2[i],z); 152 inc(tree[i],z); 153 end 154 else begin 155 push(i); 156 m:=(l+r) shr 1; 157 if x<=m then fadd(i*2,l,m,x,y); 158 if y>m then fadd(i*2+1,m+1,r,x,y); 159 tree[i]:=max(tree[i*2],tree[i*2+1]); 160 end; 161 end; 162 163 function getans(i,l,r,x,y:longint):longint; 164 var m,s:longint; 165 begin 166 if x>y then exit(0); 167 if (x<=l) and (y>=r) then exit(tree[i]) 168 else begin 169 push(i); 170 m:=(l+r) shr 1; 171 s:=0; 172 if x<=m then s:=getans(i*2,l,m,x,y); 173 if y>m then s:=max(s,getans(i*2+1,m+1,r,x,y)); 174 exit(s); 175 end; 176 end; 177 178 procedure cover(x,y:longint); 179 var f1,f2:longint; 180 begin 181 f1:=top[x]; 182 f2:=top[y]; 183 while f1<>f2 do 184 begin 185 if d[f1]>=d[f2] then 186 begin 187 change(1,1,n-1,b[fp[f1]],b[fp[x]],z); 188 x:=fa[f1]; 189 end 190 else begin 191 change(1,1,n-1,b[fp[f2]],b[fp[y]],z); 192 y:=fa[f2]; 193 end; 194 f1:=top[x]; 195 f2:=top[y]; 196 end; 197 if x=y then exit 198 else if b[fp[x]]>b[fp[y]] then swap(x,y); 199 change(1,1,n-1,b[son[x]],b[fp[y]],z); 200 end; 201 202 procedure add(x,y:longint); 203 var f1,f2:longint; 204 begin 205 f1:=top[x]; 206 f2:=top[y]; 207 while f1<>f2 do 208 begin 209 if d[f1]>=d[f2] then 210 begin 211 fadd(1,1,n-1,b[fp[f1]],b[fp[x]]); 212 x:=fa[f1]; 213 end 214 else begin 215 fadd(1,1,n-1,b[fp[f2]],b[fp[y]]); 216 y:=fa[f2]; 217 end; 218 f1:=top[x]; 219 f2:=top[y]; 220 end; 221 if x=y then exit 222 else if b[fp[x]]>b[fp[y]] then swap(x,y); 223 fadd(1,1,n-1,b[son[x]],b[fp[y]]); 224 end; 225 226 function ask(x,y:longint):longint; 227 var s,f1,f2:longint; 228 begin 229 s:=0; 230 f1:=top[x]; 231 f2:=top[y]; 232 while f1<>f2 do 233 begin 234 if d[f1]>=d[f2] then 235 begin 236 s:=max(s,getans(1,1,n-1,b[fp[f1]],b[fp[x]])); 237 x:=fa[f1]; 238 end 239 else begin 240 s:=max(s,getans(1,1,n-1,b[fp[f2]],b[fp[y]])); 241 y:=fa[f2]; 242 end; 243 f1:=top[x]; 244 f2:=top[y]; 245 end; 246 if x=y then exit(s) 247 else if b[fp[x]]>b[fp[y]] then swap(x,y); 248 s:=max(s,getans(1,1,n-1,b[son[x]],b[fp[y]])); 249 exit(s); 250 end; 251 252 begin 253 readln(n); 254 for i:=1 to n-1 do 255 begin 256 readln(x,y,a[i]); 257 add(x,y,i); 258 add(y,x,i); 259 end; 260 t:=0; 261 dfs1(1); 262 top[1]:=1; 263 dfs2(1); 264 while true do 265 begin 266 read(ch); 267 s:=''; 268 while ch<>' ' do 269 begin 270 s:=s+ch; 271 if s='Stop' then halt; 272 read(ch); 273 end; 274 read(x,y); 275 if s='Max' then 276 writeln(ask(x,y)) 277 else if s='Change' then 278 change(1,1,n-1,b[x],b[x],y) 279 else if s='Cover' then 280 begin 281 read(z); 282 cover(x,y); 283 end 284 else if s='Add' then 285 begin 286 read(z); 287 add(x,y); 288 end; 289 readln; 290 end; 291 end.
