Codeforces Round #235 (Div. 2)C、Team

#include <iostream>
#include <algorithm>

using namespace std;

int main(){
    int n,m;
    cin >> n >> m;
    if(n > (m + 1) || m > (n + 1)*2 ) cout<< -1;
    else if( n>= m) {
        for(int i = 0; i < m; ++ i) cout<<"01";
        for(int i = m; i < n; ++ i) cout<<"0";
    }else if(n*2>=m){
        for(int i = 0; i< m - n; ++ i) cout<<"110";
        for(int i =m-n; i < n; ++ i ) cout<< "10";
    }else{
        for(int i = 0 ; i < n ; ++ i) cout<<"110";
        for(int i = 0 ; i< m-2*n; ++ i) cout<<"1";
    }
    cout<<endl;
}