1038 Recover the Smallest Number (30分)

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 (≤10
​4
​​ ) 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. Notice that the first digit must not be zero.

Sample Input:
5 32 321 3214 0229 87

Sample Output:
22932132143287

这个题刚开始的时候我就想这个肯定是个bp的思想。。。。但我怎么也想不出很好的做法。。。
直到我看了某位大佬的博客

好菜啊我。。。

#include 
#include 
#include 
#include 
#include 

using namespace std;

bool cmp(string& a, string& b) {
    return a+b < b+a;
}


int main() {
    int N;
    vector vec;
    scanf("%d", &N);
    while(N--) {
        string str;
        cin >> str;
        vec.push_back(str);
    }
    sort(vec.begin(), vec.end(), cmp);
    string s = "",t = "";
	for(int i = 0 ; i < vec.size(); i ++)
		s += vec[i];
	while(s.empty() == 0 && s.at(0) == '0')
		s.replace(0,1,"");
	if(s.empty() == true)
		cout<<0<