Time complexity¶
Built-in methods¶
String¶
Operation |
Example |
Big-O |
Notes |
|---|---|---|---|
split |
split() |
O(n) |
List¶
Operation |
Example |
Big-O |
Notes |
|---|---|---|---|
slice |
list[a:b] |
O(b-a) = O(n) |
|
sum |
sum([1, 2, 3, 4, 5]) |
O(n) |
Counter¶
Operation |
Example |
Big-O |
Notes |
|---|---|---|---|
Counter |
Counter([1, 2, 3]) |
O(n) |
|
most_common |
c.most_common(2) |
O(nlogn) |
input vs. sys.stdin.readline¶
If you handle big data, it is faster to use sys.stdin.readline but I don’t know why sys.stdin.readline is fater than input.
Pandas and numpy¶
Numpy¶
Operation |
Example |
Big-O |
Notes |
|---|---|---|---|
sum |
<array>.sum([1, 2, 3, 4, 5]) |
O(n) |
Faster than built-in sum function (sum vs. np.sum) |