1 void insert_sort(vector<int> &v)
 2 {
 3     for (int i = 1; i < v.size(); ++i)
 4     {
 5         int key = v[i];
 6         int j = i - 1;
 7         while (j >= 0 && key > v[j])
 8         {
 9             v[j + 1] = v[j];
10             --j;
11         }
12         v[j + 1] = key;
13     }
14 }