Hello @eby.annie, @scarlett.patrick22,

I will try my best to clarify as I was in the same boat as you.

This is how I see it:

```
# Let's say..
N = 10
M = 20
list4 = [[i + j for j in range(M)] for i in range(N)] # N*M
list5 = [min(list4[i]) for i in range(N)]
```

This is what `list4`

holds:

```
for i, v in enumerate(list4):
print(f"{i}: {v}")
Output:
0: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
1: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
2: [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]
3: [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]
4: [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23]
5: [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
6: [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]
7: [7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]
8: [8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27]
9: [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28]
```

As you see, the length of each entry in `list4`

is not the same as `N`

.

The maximum length we see is at `list4[9]`

. It is of length 20, which is the value of `M`

.

**Letâ€™s see this for the worst-case scenario because the **`O`

rder of Time complexity is measured against the worst case:

Even though accessing a list by its index is a constant time operation `O(1)`

,

`list5 = [min(list4[i]) for i in range(N)]`

translates to:

`list5 = [min(list4[9]) for 9 in range(0..9)]`

when `i = 9`

, which again translates to:

`list5 = [min([9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28])]`

Now, what is the cost of performing `min(list4[9])`

whose size is `M`

?

The whole list of size `M`

is scanned to find the minimum.

This is the cost of the hidden operation.

So for every `N`

, the hidden cost is `M`

, which is of the `O`

rder`(N*M)`

Hope this clears it up!

Do let me know.