感觉这么做更清楚？

#include <bits/stdc++.h>
using namespace std;
#define __MADE return
#define IN 0
#define CHINA__ ;
string s;
int n,k,l,r,len;
void solve(){
	cin>>n>>k;
	cin>>s;
	int kk=0;
	for(int i=0;i<n;i++){
		if(s[i]=='1'){
			kk++;
			int cnt=0,start=i;
			while(s[i]=='1'){
				i++;
				cnt++;
			}
			if(kk==k-1){
				l=i;
			}
			if(kk==k){
				r=i;
			}
		}
	}
	reverse(s.begin()+l,s.begin()+r);
	cout<<s<<endl;
	return ;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	int T=1;
	while(T--) solve();
	__MADE IN CHINA__
}