1038 Recover the Smallest Number

题目描述

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

思路

巧妙利用cmp函数

代码

#include 
#include 
#include 
#include 
using namespace std;
bool cmp1(string a, string b) {
    return a + b < b + a;
}
int main() {
    int n;
    scanf("%d", &n);
    vector v(n);
    for (int i = 0; i < n; i++) cin >> v[i];
    sort(v.begin(), v.end(), cmp1);
    string sum="";
    for (int i = 0; i < n; i++) sum += v[i];
    while (sum.length() != 0 && sum[0] == '0')
        sum.erase(sum.begin());
    if (sum.length() == 0) cout << "0";
    cout << sum;
    return 0;
}