1038 Recover the Smallest Number （30 分）(貪心算法，神奇的cmp)

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

#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <string>
#include <cctype>
#include <string.h>
#include <cstdio>
using namespace std;
string str[10010];
bool cmp(string a,string b){
    return a+b<b+a;
}
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++)
        cin>>str[i];
    sort(str,str+n,cmp);
    string s;
    for(int i=0;i<n;i++)
        s+=str[i];
    while(s.length()!=0&&s[0]=='0')
        s.erase(s.begin());
    if(s.length()==0) cout<<"0";
    else cout<<s;
    return 0;
}