poj 3468:zkw树区间修改

那天考完，不知道怎么谈到zkw树的区间修改。于是就重温了一下zkw那坑爹的ppt...果断晕了，后来问了HUC才知道是差分。。。

维护两棵树，i*Ai,与Ai-A(I-1)

贴代码

const        find=131071;var        tree:array[1..2,0..2662144]of int64;        a:array[0..100001]of int64;        m,n:longint;procedure change(k,x:longint;w:int64);var        k1:longint;begin        x:=x+find;        tree[k,x]:=tree[k,x]+w;        k1:=x shr 1;        while k1>0 do          begin                tree[k,k1]:=tree[k,k1]+w;                k1:=k1 shr 1;          end;end;function ask(k,x,y:longint):int64;begin        x:=x+find-1; y:=y+find+1;        ask:=0;        while not (x xor y=1) do          begin                if x and 1=0 then ask:=ask+tree[k,x+1];                if y and 1=1 then ask:=ask+tree[k,y-1];                x:=x shr 1; y:=y shr 1;          end;        exit(ask);end;procedure init;var        i:longint;begin        readln(n,m);        fillchar(tree,sizeof(tree),0);        for i:=1 to n do read(a[i]);        for i:=1 to n do          begin                change(1,i,a[i]-a[i-1]);                change(2,i,i*(a[i]-a[i-1]));          end;        readln;end;procedure main;var        i,x,y:longint;        x1,ans1,ans2:int64;        z1,z2:char;begin        for i:=1 to m do          begin                read(z1,z2,x,y);                if z1='Q' then                  begin                     x:=x-1;                     ans1:=ask(1,1,y)*(y+1);                     ans1:=ans1-ask(2,1,y);                     if x<>0 then                       begin                        ans2:=ask(1,1,x)*(x+1);                        ans2:=ans2-ask(2,1,x);                       end else ans2:=0;                     writeln(ans1-ans2);                  end                    else                      begin                        read(x1);                        change(1,x,x1);  change(1,y+1,-x1);                        change(2,x,x*x1);  change(2,y+1,-(y+1)*x1)                      end;                readln;          end;end;begin        init;        main;end.