求助！20分 C++

#include<iostream>
#include<cstring>
#include<cmath>
using namespace std;
char a[50000];
int main(){
	int i=0;
	while(cin>>a[i]) i++;
	int n;
	n=sqrt(i);
	cout<<n<<" ";
	int one=0,zero=0;
	for(int j=0;j<=i;j++){
		if(a[j]=='\0'){
			if(one!=0) cout<<one;
			if(zero!=0) cout<<zero;
		}
		if(a[j]=='0'){
			if(one!=0) cout<<one<<" ";
			one=0;
			zero++;
		}
		if(a[j]=='1'){
			if(zero!=0) cout<<zero<<" ";
			zero=0;
			one++;
		}
	}
	return 0;
}