PKU 2777 线段树

http://hi.baidu.com/raulliubo/blog/item/24587160e34cff40eaf8f865.html

在众多大牛的指点下AC了。以前总WA竟然是因为数组开小了。。。这不应该是RE吗。。怎么WA了。抑郁了，还以为算法错了。这题考的就是线段树加二进制储存信息。。。。

my ugly code:

var
    color, left, right : array[1 .. 1000000] of longint;
    order : char;
    i, count, temp, a, b, len, t, o, c : longint;

procedure buildtree(now, l, r : longint);
var
    mid : longint;
begin
    if l = r then begin
        left[now] := l;
        right[now] := r;
        exit;
    end;
    left[now] := l;
    right[now] := r;
    mid := (left[now] + right[now]) shr 1;
    buildtree(now * 2, l, mid);
    buildtree(now * 2 + 1, mid+1, r);
end;

function single(x : longint) : boolean;
begin
    exit((x - 1) and x = 0);
end;

procedure insert(now, l, r, co : longint);
var
    mid : longint;
begin
    if (l <= left[now]) and (r >= right[now]) then begin
        color[now] := co;
        exit;
    end;
    if color[now] = co then
        exit;
    if single(color[now]) then begin
        color[2*now] := color[now];
        color[2*now + 1] := color[now];
    end;
    mid := (left[now] + right[now]) shr 1;
    if l <= mid then
        insert(now * 2, l, r, co);
    if r > mid then
        insert(now * 2 + 1, l, r, co);
    color[now] := color[now * 2] or color[now * 2 + 1];
end;

procedure search(now, l, r : longint);
var
    mid : longint;
begin
    if (l <= left[now]) and (r >= right[now]) then begin
        count := count or color[now];
        exit;
    end;
    if single(color[now]) then begin
        count := count or color[now];
        exit;
    end;
    mid := (left[now] + right[now]) shr 1;
    if l <= mid then    
        search(now * 2, l, r);
    if r > mid then
        search(now * 2 + 1, l, r);
end;

function ans(c : longint) : longint;
var
    i, cnt : longint;
begin
    cnt := 0;
    while c > 0 do begin
        if c mod 2 = 1 then
            inc(cnt);
        c := c shr 1;
    end;
    exit(cnt);
end;       
   
begin
    readln(len, t, o);
    buildtree(1, 1, len);
    insert(1, 1, len, 1);
    for i := 1 to o do begin
        read(order);
        case order of
            'C' :
            begin
                readln(a, b, c);
                if a > b then begin
                    temp := a;
                    a := b;
                    b := temp;
                end;
                insert(1, a, b, 1 shl (c-1));
            end;
            'P' :
            begin
                readln(a, b);
                if a > b then begin
                    temp := a;
                    a := b;
                    b := temp;
                end;
                count := 0;
                search(1, a, b);
                writeln(ans(count));
            end;
        end;
    end;
end.