题解 | #本场比赛灵感来源于树状数组出题组#

这条题目本质是最大化所有子串的mex之和，即最大化同时包含0和1的子串数量、

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T;
    cin >> T;
    while (T--) {
        int a, b;
        cin >> a >> b;
        string s;
        if (a == 0) {
            s = string(b, '1');
        } else if (b == 0) {
            s = string(a, '0');
        } else if (a >= b) {
            int m = b + 1;
            int base = a / m;
            int rem = a % m;
            for (int i = 0; i < b; ++i) {
                s += string(rem > 0 ? base + 1 : base, '0');
                if (rem > 0) rem--;
                s += '1';
            }
            s += string(base, '0');
        } else {
            int m = a + 1;
            int base = b / m;
            int rem = b % m;
            for (int i = 0; i < a; ++i) {
                s += string(rem > 0 ? base + 1 : base, '1');
                if (rem > 0) rem--;
                s += '0';
            }
            s += string(base, '1');
        }
        cout << s << '\n';
    }
    return 0;
}