1038 Recover the Smallest Number (30分) (贪心 cmp牛比)

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 (≤) 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 <vector>
using namespace std;

vector<string> v;
bool cmp(string a, string b) {
    return a + b < b + a;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif // ONLINE_JUDGE
    int n;
    cin >> n;
    for(int i = 0; i < n; i++) {
        string s;
        cin >> s;
        v.push_back(s);
    }
    sort(v.begin(), v.end(), cmp);
    string ans = "";
    for(int i = 0; i < v.size(); i++)
        ans += v[i];
    while(*ans.begin() == '0') {
        ans.erase(ans.begin());
    }
    if(ans == "") cout << 0;
    else cout << ans;

    return 0;
}