技術標籤：PAT演算法

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

分析：

1、貪心，sort裡cmp的神應用，膜拜大佬柳婼；也運用了string str 裡面刪除單個元素用str.erase(迭代器)

2、測試點2出錯是沒有考慮全零的情況，要特判

我的程式碼：

#include<bits/stdc++.h>
using namespace std;
bool cmp(string s1,string s2)
{
    return s1 + s2 < s2 + s1;
}
int main()
{
    int
 
 n,k = 0;
    scanf("%d",&n);
    vector<string> v;
    for (int i = 0 ;i < n ;i++)
    {
        string str;
        cin >> str;
        v.push_back(str);
    }
    sort(v.begin(),v.end(),cmp);
    string str;
    for (int i = 0 ;i < v.size() ;i++)
        str += v[i];
    while (str[0] == '0')
        str.erase(str.begin());
    if (str.size() == 0)
        printf("0");
    else
        printf("%s",str.c_str());
    return 0;
}