Largest Number - Implementation

Here is the implementation:

function largestNumber(nums):
    strs = convert nums to strings

    sort strs with comparator:
        compare(a, b): return (b + a) compared to (a + b)

    if strs[0] == "0":
        return "0"

    return join(strs, "")

The edge case check handles inputs like [0, 0] which should return "0" not "00".

Sorting takes $O(n \log n)$ comparisons. Each comparison is $O(k)$ where $k$ is digit count. Total: $O(nk \log n)$ time.