L1_027出租

• 比起for循环string再内层for循环vector找到数字并得到下标
  vector排序完成后，遍历一遍用一个数组来存每个数的下标，之后在循环一次string直接根据值去数组索引高效得多
  用空间换时间

#include 
#include 
#include 
#include 
using namespace std;
int main()
{
    string tel;
    cin >> tel;
    int num[10] = { 0 };
    vector exnum;
    for (int i = 0; i < tel.size(); ++i) {
        if (!num[tel[i] - '0']) {
            num[tel[i] - '0'] = 1;
            exnum.push_back(tel[i]-'0');
        }
    }
    sort(exnum.rbegin(), exnum.rend());
    cout << "int[] arr = new int[]{";
    for (int i = 0; i < exnum.size(); ++i) {
        num[exnum[i]] = i;
        if (i)
            cout << ",";
        cout << exnum[i];
    }
    cout << "};"<