Form the Maximum Number from Array Elements

Problem Given an array of non-negative integers, arrange them so that concatenating their decimal representations forms the largest possible number.

Input / Output

• Input: array nums of non-negative integers.
• Output: the largest concatenation, returned as a string (it can exceed 64-bit range).

Constraints

• Up to ~10^4 elements, each with varying digit length.
• Values are non-negative; the result must be returned as a string since the concatenation may be far larger than any integer type.

Example

• Input: [3, 30, 34, 5, 9] → Output: "9534330"
• Tricky cases: [3, 30] → "330", not "303" — sorting numerically or lexicographically both give the wrong answer here. And [0, 0] → "0", not "00": the all-zeros input must be collapsed.