regular update

Author: coderxiang

Codeforces/150C_107.cpp

@@ -53,10 +53,7 @@ qtype query (int u, int x, int y) {
 	qtype a = {-1e20, -1e20, -1e20}, b = {-1e20, -1e20, -1e20}, ret;
 	if (x <= mid) a = query (u<<1, x, y);
 	if (y > mid) b = query (u<<1|1, x, y);
-	ret.ma = max(a.ma, b.ma);
-	if (x <= mid && y > mid) {
-		ret.ma = max (ret.ma, a.mr + b.ml);
-	}
+	ret.ma = max (max (a.ma, b.ma), a.mr + b.ml);
 	ret.ml = a.ml;
 	if (x <= L[u] && y > mid)
 		ret.ml = max (ret.ml, sum[u<<1] + b.ml);

Codeforces/150C_107.ml

@@ -0,0 +1,85 @@
+let ( |> ) v f = f v
+let ( <| ) f v = f v
+let foi = float_of_int
+let iof = int_of_float
+
+let next_int () = Scanf.scanf "%d%c" (fun x _ -> x)
+let next_flt () = Scanf.scanf "%f%c" (fun x _ -> x)
+
+let rec show_flt_list a = 
+  match a with
+	  [] -> print_newline ()
+	| x::xs -> print_float x; print_string " "; show_flt_list xs
+
+
+let rec loop n f acc = 
+  if n = 0 then List.rev acc
+  else loop (n - 1) f ( (f n) :: acc)
+  
+
+type data = {ma : float; lv : float; rv : float; sum : float}
+type range = {l: int; r : int}
+
+type seg_tree = 
+  Leaf of data
+| Node of int * int * data * seg_tree * seg_tree
+
+
+let get_data tr = 
+  match tr with
+	  Leaf d
+	| Node (_, _, d, _, _) -> d
+
+
+let update dlc drc = 
+  let s = dlc.sum +. drc.sum in
+  let l = max dlc.lv (dlc.sum +. drc.lv) in
+  let r = max drc.rv (drc.sum +. dlc.rv) in
+  let m = max (max dlc.ma drc.ma) (dlc.rv +. drc.lv) in
+  {ma = m; lv = l; rv = r; sum = s;}
+;;
+
+let n = next_int () 
+let m = next_int ()
+let c = next_flt () 
+
+let d = loop n (fun _ -> next_flt ()) []
+let p = loop (n - 1) (fun _ -> ((next_flt ()) /. 100.0)) []
+
+let v = List.map (fun (a, b) -> a -. b) (List.combine (List.tl d) (List.rev (List.tl (List.rev d))))
+let a = Array.of_list <| List.map (fun (a, b) -> a /. 2.0 -. b *. c) (List.combine v p)
+
+
+let rec build x y =
+  if x = y then Leaf ({ma = max (foi 0) a.(x); lv = a.(x); rv = a.(x); sum = a.(x)})
+  else begin
+	let mid = (x + y) / 2 in
+	let lc = build x mid in
+	let rc = build (mid+1) y in
+	Node (x, y, (update (get_data lc) (get_data rc)), lc, rc)
+  end
+
+let rec query tr x y =
+  match tr with
+	  Leaf d -> d
+	| Node (l, r, d, lc, rc) -> begin
+	  if x <= l && y >= r then d
+	  else
+		let mid = (l + r) / 2 in
+		let snt = {ma = -1e20; lv = -1e20; rv = -1e20; sum = -1e20} in
+		let qlc = if x <= mid then query lc x y else snt in
+		let qrc = if y > mid then query rc x y else snt in
+		update qlc qrc
+	end
+
+let tr = build 0 (n - 2)
+
+let () =
+  loop m (fun _ -> (let a = next_int() in
+					let b = next_int() in
+					query tr (a - 1) (b - 2)).ma) []  
+	|> List.fold_left (+.) (foi 0) 
+	|> print_float
+  
+
+