44分求大佬帮忙

#include<bits/stdc++.h>
using namespace std;
string s;
int k , a[255] , n = 1;
int main()
{
	cin >> s;
	cin >> k;
	for (int i = 0;i < s.size();i ++){
		a[n] = s[i] - '0';
		n ++;
	}
	n-=1;
	sort (a+1,a+1+n);
	if (n - k == 0){
		cout << 0;
	}else {
		for (int i=1;i<=n-k;i++)cout<<a[i];
	}
	return 0;
}