Split the binary string into substrings with equal number of 0s and 1s

#include<bits/stdc++.h>
using namespace std;

int solve(string s)
{
    int count0=0;
    int count1=0;
    int count=0;
    int n = s.size();

    for(int i=0 ; i<n ; i++)
    {
        if(s[i]=='0')   count0++;
        else    count1++;

        if(count0==count1)  count++;
    }
        if(count1!=count0)  return -1;
        return count;
}

int main()
{
    string s = "0100110101";
    cout<<solve(s)<<endl;
    return 0;
}

//Time Complexity - O(n)
//Space Complexity - O(1)