leetcode 179. Largest Number

Posted 2020-10-02 いいえ敗者

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.

一开始写了半天比较函数，后来反应过来，可以用字符串相加后比较来确定 a串还是b串对总大小的贡献大小

写个比较函数就可以了，注意0的情况。

 1 class Solution {
 2 public:
 3     static bool cmp(const string& a, const string& b) {
 4         return (a+b) > (b+a);
 5     }
 6     string largestNumber(vector<int>& nums) {
 7         vector<string> v;
 8         int sum = 0;
 9         for (int i = 0; i < nums.size(); ++i) {
10             v.push_back(to_string(nums[i]));
11             sum += nums[i];
12         }
13         if (sum == 0) return "0";
14         sort(v.begin(), v.end(), cmp);
15         string k = "";
16         for (int i = 0; i < nums.size(); ++i) {
17             k += v[i];
18         }
19         return k;
20     }
21 };