NOI 项链工厂

原题：NOI 项链工厂

方法：线断树

program necklace;const    maxn=500000;var    ls,rs,s,cl,cr,z:array[1..maxn shl 2]of longint; sto,col,cur:longint; rev:boolean;procedure update(const x:longint);begin    cl[x]:=cl[ls[x]]; cr[x]:=cr[rs[x]];    s[x]:=s[ls[x]]+s[rs[x]]-ord(cr[ls[x]]=cl[rs[x]]);end;procedure build(var x:longint;const l,r:longint);var mid:longint;begin    inc(sto); x:=sto; mid:=(l+r)>>1;    if l=r then begin read(cl[x]); cr[x]:=cl[x]; s[x]:=1; exit; end;    build(ls[x],l,mid);build(rs[x],mid+1,r); update(x);end;procedure put(const x,cc:longint);begin    cl[x]:=cc; cr[x]:=cc; z[x]:=cc; s[x]:=1;end;procedure modify(const x,cc:longint);begin    if cc=0 then exit;    if ls[x]<>0 then put(ls[x],cc);    if rs[x]<>0 then put(rs[x],cc); z[x]:=0;end;function get_c(const x,l,r,k:longint):longint;var mid:longint;begin    if z[x]<>0 then exit(z[x]); mid:=(l+r)>>1;    if k=l then exit(cl[x]);if k=r then exit(cr[x]);    if k<=mid then exit(get_c(ls[x],l,mid,k));    exit(get_c(rs[x],mid+1,r,k));end;function get(const x,l,r,ll,rr:longint):longint;var mid:longint;begin    modify(x,z[x]); mid:=(l+r)>>1;    if (ll=l)and(rr=r) then exit(s[x]);    if rr<=mid then exit(get(ls[x],l,mid,ll,rr)) else    if ll>mid then exit(get(rs[x],mid+1,r,ll,rr)) else    get:=get(ls[x],l,mid,ll,mid)+get(rs[x],mid+1,r,mid+1,rr)-ord(cr[ls[x]]=cl[rs[x]]);end;procedure change(const x,l,r,k:longint);var mid:longint;begin    modify(x,z[x]);mid:=(l+r)>>1;    if (l=r) then begin cl[x]:=col; cr[x]:=col; exit; end;    if k<=mid then change(ls[x],l,mid,k) else change(rs[x],mid+1,r,k);    update(x);end;procedure change(const x,l,r,ll,rr:longint);var mid:longint;begin    modify(x,z[x]);mid:=(l+r)>>1;    if (l=ll)and(r=rr) then begin put(x,col); exit; end;    if rr<=mid then change(ls[x],l,mid,ll,rr) else    if ll>mid then change(rs[x],mid+1,r,ll,rr) else beginchange(ls[x],l,mid,ll,mid);change(rs[x],mid+1,r,mid+1,rr);    end;update(x);end;var n,m,x,y,i,j:longint;ch:char; tmp_tot:integer;function g(const x:longint):longint;begin    g:=cur; if not rev then inc(g,x-1) else inc(g,n-x+1);    if g>n then dec(g,n);end;Begin    assign(input,'input.txt');reset(input);assign(output,'output.txt');rewrite(output);    readln(n,m); build(x,1,n); readln(m); rev:=false;cur:=1;    for m:=1 to m do beginrepeat read(ch); until ch in ['R','F','P','C','S'];if ch='C' then begin        if eoln then writeln(s[1]-ord(cl[1]=cr[1])+ord(s[1]=1)) else begin    read(ch);read(i,j);i:=g(i);j:=g(j);    if (not rev)then if (i<=j) then writeln(get(1,1,n,i,j)) else    writeln(get(1,1,n,1,j)+get(1,1,n,i,n)-ord(cl[1]=cr[1])) else    if (j<=i) then writeln(get(1,1,n,j,i)) else    writeln(get(1,1,n,1,i)+get(1,1,n,j,n)-ord(cl[1]=cr[1]));end; end else if ch='R' then begin read(x);    if rev then inc(cur,x) else inc(cur,n-x); if cur>n then dec(cur,n);end else if ch='F' then rev:=not revelse if ch='S' then begin    readln(i,j);i:=g(i);j:=g(j);    x:=get_c(1,1,n,i);y:=get_c(1,1,n,j);    if x=y then continue;    col:=y;change(1,1,n,i);col:=x;change(1,1,n,j);end else if ch='P' then begin    read(i,j,col);i:=g(i);j:=g(j);    if (not rev)then if(i<=j) then change(1,1,n,i,j) else begin    change(1,1,n,1,j);change(1,1,n,i,n);end else    if (j<=i) then change(1,1,n,j,i) else begin    change(1,1,n,1,i);change(1,1,n,j,n);end;end;    end;    close(input);close(output);end.