点击链接PAT甲级-AC全解汇总

题目：
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
1

Sample Output:

22932132143287
1

题意：
输入一堆数，看怎么拼比较小；

我的思路：
比较拼接后哪种情况小，就哪种方法排序，然后把结果拼到一起输出

注意： 把拼完的结果前面的0都删掉，如果删光了，还要输出一个0

我的代码：

#include
using namespace std;

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

int main(){
    vector<string>nums;
    int N;
    cin>>N;
    for(int i=0;i<N;i++)
    {
        string num;
        cin>>num;
        nums.push_back(num);
    }

    sort(nums.begin(),nums.end(),cmp);
    string res;
    for(auto s:nums)res+=s;//拼到一起

    while(res[0]=='0')res.erase(0,1);//头上的0删掉

    if(!res.size())cout<<"0"<<endl;
    else cout<<res<<endl;
    return 0;
}


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