179. Largest Number LeetCode Solution | Easy Approach

Largest Number Given a list of non-negative integers nums, arrange them such that they form the largest number and return it.

Since the result may be very large, so you need to return a string instead of an integer.

Example 1:

Input: nums = [10,2]
Output: "210"

Example 2:

Input: nums = [3,30,34,5,9]
Output: "9534330"

Constraints:

• 1 <= nums.length <= 100

Largest Number Solutions

✅Time: O(n log n)
✅Space: O(n)

C++

class Solution {
 public:
  string largestNumber(vector<int>& nums) {
    string ans;

    sort(begin(nums), end(nums), [](int a, int b) {
      return to_string(a) + to_string(b) > to_string(b) + to_string(a);
    });

    for (const int num : nums)
      ans += to_string(num);

    return ans[0] == '0' ? "0" : ans;
  }
};

Java

 
class Solution {
  public String largestNumber(int[] nums) {
    final String s = Arrays.stream(nums)
                         .mapToObj(String::valueOf)
                         .sorted((a, b) -> (b + a).compareTo(a + b))
                         .collect(Collectors.joining(""));
    return s.startsWith("00") ? "0" : s;
  }
}

Python

 class LargerStrKey(str):
  def __lt__(x: str, y: str) -> bool:
    return x + y > y + x


class Solution:
  def largestNumber(self, nums: List[int]) -> str:
    return ''.join(sorted(map(str, nums), key=LargerStrKey)).lstrip('0') or '0'

Watch Tutorial

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