added some solutions

Author: Alice

hw1-1.ml

@@ -0,0 +1,5 @@
+let rec sigma(a,b,f) =
+	if a>b-1 then 0
+	else f(b) + sigma(a,b-1,f)
+
+(*let _ = print_int(sigma(3,2,fun x->x+2))*)

hw1-2.ml

@@ -0,0 +1,37 @@
+let sumprod(f,n,k) = 
+	let x = ref 0.0 in
+	let y = ref 1.0 in
+	for i=1 to n do
+		for j=1 to k do
+			y := !y *. f(i,j)
+		done;
+		x := !x +. !y;
+		y := 1.0
+	done;
+	!x
+
+(*Hello World*)
+(*
+let rec mult(b,f) =
+	if b<=0 then 1.0
+	else f(b) *. mult(b-1,f)
+
+
+let rec sigma(a,f) =
+	if a<=0 then 0.0
+	else f(a) +. sigma(a-1,f)
+*)
+
+(*let rec sumprod(M,n,k) =
+	let x = ref 0.0 in
+	let y = ref 0.0 in
+	let kk = ref k in
+	match (n,k) with
+		| (0,0) -> !x
+		| (0,k') -> !x
+		| (n',0) -> x := !x + !y; y := 0.0; sumprod(M,n'-1,!kk)
+		| (n',k') -> y := !y * M(n',k') ;sumprod(M,n',k'-1)
+
+let em(a,b) = (float_of_int a)/.(float_of_int b)
+*)
+

hw1-3.ml

@@ -0,0 +1,10 @@
+type team = Korea | France | Usa | Brazil | Japan | Nigeria | Cameroon
+| Poland | Portugal | Italy | Germany | Norway | Sweden | England
+| Argentina
+
+type tourna = LEAF of team
+	    | NODE of tourna * tourna
+
+let rec parenize tr =
+	match tr with
+		| NODE tr' ->  

hw14.ml renamed to hw1-5.ml

@@ -1,4 +1,4 @@
-t = ZERO | SUCC of nat
+type nat = ZERO | SUCC of nat
 
 let rec natadd (a,b) =
 	match(a,b) with