PAT Grade A-1038 Recover the Smallest Number (30 points)

Title: 1038 Recover the Smallest Number (30 points)

Analysis : simulation is enough, sort sorts strings, mainly processing prefix 0, see the code

#include <iostream>
#include<cstring>
#include<vector>
#include<stdio.h>
#include<queue>
#include<math.h>
#include<stack>
#include<algorithm>
#include<map>
#include<set>
#define MAX 99999999
typedef long long ll;
using namespace std;
int n,m;
string a[100001];
int cmp(string s1,string s2)
{
    
    
    return s1 + s2 < s2 + s1;
}
int main()
{
    
    
    cin>>n;
    for(int i = 0;i<n;i++)
    cin>>a[i];
    sort(a,a+n,cmp);
    string ans ;
    for(int i = 0;i<n;i++)
        ans += a[i];
    int i = 0;
    for(;i<ans.size()&&ans[i]=='0';i++);
    if(i == ans.size())
        cout<<0;
    for(;i<ans.size();i++)
        cout<<ans[i];
    return 0;
}