Add a bunch more stuff

Codeforces Round 973 (Div. 2)/C. Password Cracking.cpp

@@ -0,0 +1,163 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2013/C */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+void pre()
+{
+
+}
+
+#define TEST 1
+
+void solve()
+{
+    int n;
+    cin >> n;
+
+    auto ask = [&](string a) {
+        cout << "? " << a << endl;
+        int ans;
+        cin >> ans;
+        return ans;
+    };
+
+    auto answer = [&](string a) {
+        cout << "! " << a << endl;
+    };
+
+    if (n == 1) {
+        bool t = ask("0");
+        if (t) {
+            answer("0");
+        } else {
+            answer("1");
+        }
+        return;
+    }
+
+    string ans;
+    if (ask("0")) {
+        ans = "0";
+    } else {
+        ans = "1";
+    }
+
+    bool back = false;
+    rep(i, n - 1) {
+        if (back) {
+            if (ask("0" + ans)) {
+                ans = "0" + ans;
+                continue;
+            }
+
+            ans = "1" + ans;
+            continue;
+        }
+
+        if (ask(ans + "0")) {
+            ans += "0";
+            continue;
+        }
+
+        if (ask(ans + "1")) {
+            ans += "1";
+            continue;
+        }
+
+        back = true;
+        i--;
+    }
+
+    answer(ans);
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}