Leetcode 179. Largest Number

https://leetcode.com/problems/largest-number/

Note: we now only care about algorithm problems. So some problems are ignored.

Using built-in function will make it simple.

Solution:

# T:O(nlgn) S:O(1)
class Solution:
    # @param num, a list of integers
    # @return a string
    def largestNumber(self, num):
        num = [str(x) for x in num]
        num.sort(cmp=lambda x, y: cmp(y + x, x + y))
        largest = ''.join(num)
        return largest.lstrip('0') or '0'

Run Time: 64 ms