LeetCode

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.

Credits:

给出一个数组，拼出最大的数。

将数字按字典序排序，严格来说，是按s1 + s2 > s2 + s1来排序，然后拼起来。

时间复杂度O(nlgn)，空间复杂度O(1)

class Solution {public:    string largestNumber(vector<int>& nums) {        vector<string> mie;        for (auto x: nums) {            mie.push_back(to_string(x));        }        sort(mie.begin(), mie.end(), cmp);        string ans = "";        for (int i = 0; i < nums.size(); ++i) {            ans += mie[i];        }        while (ans[0] == '0' && ans.length() > 1)            ans.erase(0, 1);        return ans;    }private:    static bool cmp(const string& a, const string& b) {        return a+b > b+a;    }};