把数组排成最小的数/1038. Recover the Smallest Number

题目描述

输入一个正整数数组，把数组里所有数字拼接起来排成一个数，打印能拼接出的所有数字中最小的一个。例如输入数组{3，32，321}，则打印出这三个数字能排成的最小数字为321323。

 

Given a collection of number segments, you are supposed to recover the smallest number from them. For example, given {32, 321, 3214, 0229, 87}, we can recover many numbers such like 32-321-3214-0229-87 or 0229-32-87-321-3214 with respect to different orders of combinations of these segments, and the smallest number is 0229-321-3214-32-87.

Input Specification:

Each input file contains one test case. Each case gives a positive integer N (<=10000) followed by N number segments. Each segment contains a non-negative integer of no more than 8 digits. All the numbers in a line are separated by a space.

Output Specification:

For each test case, print the smallest number in one line. Do not output leading zeros.

Sample Input:

5 32 321 3214 0229 87

Sample Output:

22932132143287

class Solution
{
    public:        
        string PrintMinNumber(vector<int> num)
        {
            string ans = "";
            int len = num.size();
            if(len==0)
                return ans;
            vector<string> nums(len);
            for(int i = 0; i<len; i++)
                nums[i] = to_string(num[i]);
            sort(nums.begin(),nums.end(),cmp);
            for(int i = 0; i<len; i++)
                ans+=nums[i];
            return ans;
        }
        static int cmp(const string &s1,const string &s2)
        {
            return s1+s2<s2+s1;
        }
};