first commit - Big O exercise

big_o_exercise/readme.md

@@ -4,16 +4,26 @@
 
 Simplify the following big O expressions as much as possible:
 
-1. `O(n + 10)`
+1. `O(n + 10)`  
+// O(n)
 2. `O(100 * n)`
-3. `O(25)`
+// O(n)
+3. `O(1)`
+// O(n)
 4. `O(n^2 + n^3)`
+// O(n^3)
 5. `O(n + n + n + n)`
+// O(n)
 6. `O(1000 * log(n) + n)`
+// log(n)
 7. `O(1000 * n * log(n) + n)`
+// nlog(n)
 8. `O(2^n + n^2)`
+// O(n^2)
 9. `O(5 + 3 + 1)`
+// O(1)
 10. `O(n + n^(1/2) + n^2 + n * log(n)^10)`
+// O(n^2)
 
 ### Part 2
 
@@ -29,6 +39,12 @@ function logUpTo(n) {
     }
 }
 
+
+time: O(n)
+space: O(1)
+
+
+
 // 2. 
 
 function logAtMost10(n) {
@@ -37,6 +53,10 @@ function logAtMost10(n) {
     }
 }
 
+time: O(1)
+space: O(1)
+
+
 // 3. 
 
 function logAtLeast10(n) {
@@ -45,6 +65,9 @@ function logAtLeast10(n) {
     }
 }
 
+time: O(n)
+space: O(1)
+
 // 4.
 
 function onlyElementsAtEvenIndex(array) {
@@ -57,6 +80,10 @@ function onlyElementsAtEvenIndex(array) {
     return newArray;
 }
 
+time: O(n)
+space: O(n)
+
+
 // 5. 
 
 function subtotals(array) {
@@ -70,4 +97,8 @@ function subtotals(array) {
     }
     return subtotalArray;
 }
+
+time: O(n^2)
+space: O(n)
+
 ```