knapsack: use const where possible

exercises/practice/knapsack/test_knapsack.nim

@@ -3,62 +3,62 @@ import knapsack
 
 suite "knapsack":
   test "no items":
-    let maximumWeight = 100
-    let items: array[0, tuple[weight: int, value: int]] = []
-    let expected = 0
+    const maximumWeight = 100
+    const items: array[0, tuple[weight: int, value: int]] = []
+    const expected = 0
     check maximumValue(maximumWeight, items) == expected
 
   test "one item, too heavy":
-    let maximumWeight = 10
-    let items = [(weight: 100, value: 1)]
-    let expected = 0
+    const maximumWeight = 10
+    const items = [(weight: 100, value: 1)]
+    const expected = 0
     check maximumValue(maximumWeight, items) == expected
 
   test "five items (cannot be greedy by weight)":
-    let maximumWeight = 10
-    let items = [
+    const maximumWeight = 10
+    const items = [
       (weight: 2, value: 5), (weight: 2, value: 5), (weight: 2, value: 5),
       (weight: 2, value: 5), (weight: 10, value: 21)
     ]
-    let expected = 21
+    const expected = 21
     check maximumValue(maximumWeight, items) == expected
 
   test "five items (cannot be greedy by value)":
-    let maximumWeight = 10
-    let items = [
+    const maximumWeight = 10
+    const items = [
       (weight: 2, value: 20), (weight: 2, value: 20), (weight: 2, value: 20),
       (weight: 2, value: 20), (weight: 10, value: 50)
     ]
-    let expected = 80
+    const expected = 80
     check maximumValue(maximumWeight, items) == expected
 
   test "example knapsack":
-    let maximumWeight = 10
-    let items = [
+    const maximumWeight = 10
+    const items = [
       (weight: 5, value: 10), (weight: 4, value: 40), (weight: 6, value: 30),
       (weight: 4, value: 50)
     ]
-    let expected = 90
+    const expected = 90
     check maximumValue(maximumWeight, items) == expected
 
   test "8 items":
-    let maximumWeight = 104
-    let items = [
+    const maximumWeight = 104
+    const items = [
       (weight: 25, value: 350), (weight: 35, value: 400), (weight: 45, value: 450),
       (weight: 5, value: 20), (weight: 25, value: 70), (weight: 3, value: 8),
       (weight: 2, value: 5), (weight: 2, value: 5)
     ]
-    let expected = 900
+    const expected = 900
     check maximumValue(maximumWeight, items) == expected
 
   test "15 items":
-    let maximumWeight = 750
-    let items = [
+    const maximumWeight = 750
+    const items = [
       (weight: 70, value: 135), (weight: 73, value: 139), (weight: 77, value: 149),
       (weight: 80, value: 150), (weight: 82, value: 156), (weight: 87, value: 163),
       (weight: 90, value: 173), (weight: 94, value: 184), (weight: 98, value: 192),
       (weight: 106, value: 201), (weight: 110, value: 210), (weight: 113, value: 214),
       (weight: 115, value: 221), (weight: 118, value: 229), (weight: 120, value: 240)
     ]
-    let expected = 1458
+    const expected = 1458
     check maximumValue(maximumWeight, items) == expected