sort
vector用法
将b[i]里的每个数在b[i]内进行快排
vector<int>b[5211314];
for (int i = 1; i <= pos[n]; ++ i) {
sort(b[i].begin(), b[i].end());
}
将b[i]里的每个数在b[i]内进行快排
vector<int>b[5211314];
for (int i = 1; i <= pos[n]; ++ i) {
sort(b[i].begin(), b[i].end());
}