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

呃呃呃呃呃以前寫過，但是感覺自己還是不開竅 直接比較字串a+b和b+a哪個比較小即可

程式碼：

#include<bits/stdc++.h>
using namespace std;
vector<string>vec;
bool cmp(string a, string b){
	return a + b < b + a;
}
int main()
{
	int n;
	scanf("%d", &n);
	char str[10];
	for(int i = 0 ; i < n ; i ++)
	{
		scanf("%s",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<<endl;
	else 
		cout<<s<<endl;
	return 0;
}