LeetCode Q179: Largest Number

Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.

Solution:

Since we need to decide which number is in front of another for each pair of numbers, we could come up a new rule for comparison in sort function.

	class Solution {
	public:
	string largestNumber(vector<int>& num) {
	sort(num.begin(), num.end(), [](int a, int b) { return to_string(a)+to_string(b) > to_string(b)+to_string(a); });
	string res;
	for(int i=0; i<num.size(); i++)
	res=res+to_string(num[i]);
	return res[0]=='0' ? "0":res;
	}
	};

view raw Q179LargestNumber.cpp hosted with ❤ by GitHub