WA84on#7玄关球条

#include <iostream>
#include <string>
using namespace std;
using ll=long long;
const ll INF=1LL<<60;
const int N=1e3+5;
ll k,minp,st,len;
string str,ans,num;
int main(){
	getline(cin,num);
    len=num.length();
    bool f=0;
    for(int i=0;i<len;i++){
        if(num[i]!='0')f=1;
        if(f)str+=num[i];
    }
    cin>>k;
    len=str.length();
    k=len-k;
    while(k--){
        minp=st;
        for(int i=st;i<len-k;i++){
            if(str[i]<str[minp]){
                minp=i;
            }
        }
        ans+=str[minp];
        st=minp+1;
    }
    ll i=0;
    len=ans.length();
    while(i<len&&ans[i]=='0')i++;
    if (i==len)cout<<'0'<<endl;
    else cout<<ans.substr(i);
	return 0;
}