C. Team

This is a chanllenging problem on codeforces with a diffcuilt score of 1400.

It presents a intressting chanllege that can be solved by using the principle of constructive.

point 1:There are no answers if m < n - 1.
point 2:There are no answers if m > (n - 1) * 2

Returning to the constructive part, If m == n - 1, we should set 0 as the leading number of the sequence.Otherwise, we can set 1 as the leading number, followed by 10,until the number of m is equal to the number of n. After that, we simply output 10 until the numbers become 0.

https://codeforces.com/problemset/problem/401/C

void solve(){
    int n, m;
    cin >> n >> m;

    if (m < n - 1 || m > (n + 1) * 2){
        cout << -1 << '\n';
    }
    else if (m == n - 1){
        while (n -- >= 2){
            cout << "01";
        }
        cout << 0;
    }
    else{
        while (n > 0 && m > 0){
            if (m > n){
                cout << "110";
                m -= 2;
                n -= 1;
            }
            else{
                cout << "10";
                m --;
                n --;
            }
        }
        while (m --){
            cout << 1;
        }
    }
}