Fix4

u2/list_ops.py

@@ -56,27 +56,41 @@ def map(function, seq):
 
 
 def foldl(function, seq, acc):
-    sum = 0 
+    if seq == []:
+        return acc
     for i in seq:
-        sum = acc + function(acc, i)
-    return sum
+        acc =function(acc, i)
+    return acc
     """Spracuje prvky zľava doprava. Akumulácia začína hodnotou acc a pri každom prvku sa použije volanie function(accumulator, element)."""
     pass
 
 
 def foldr(function, seq, acc):
-    sum = 0
-    for i in reversed(seq): # reversed міняє індекси але не сам список діє лише на 1 крок
-        sum = acc + function(acc, i)
-    return sum
+    if seq == []:
+            return acc
+    a = 0
+    for i in seq:
+        a += 1
+    i = a
+    while i >=0:
+        acc = function(acc, seq[i])
+        i -= 1
+    return acc
     """Spracuje prvky sprava doľava. Akumulácia začína hodnotou acc a pri každom prvku sa použije volanie function(accumulator, element)."""
     pass
 
 
 def reverse(seq):
-    a = []
-    for i in reversed(seq):
-        a.append(i)
-    return a
+    if seq == []:
+        return seq
+    a = 0
+    for i in seq:
+        a += 1
+    i = a
+    b = []
+    while i >=0:
+        b.append(seq[i])
+        i -= 1
+    return b
     """Vráti nový zoznam s prvkami v opačnom poradí."""
     pass