new: Codeforces Round 979 (Div. 2)

solutions/Codeforces/Codeforces Round 979 (Div. 2)/A.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+void solve() {
+   int n;
+   cin >> n;
+   long long maxi = 0, mini = INT_MAX;
+   for (int i = 0; i < n; i++) {
+      long long x;
+      cin >> x;
+      maxi = max(maxi, x);
+      mini = min(mini, x);
+   }
+
+   auto score = (n - 1) * (maxi - mini);
+   cout << score << "\n";
+}
+
+int main() {
+   ios::sync_with_stdio(false);
+   cin.tie(0);
+   cout.tie(0);
+
+   int t = 1;
+   cin >> t;
+   while (t--) solve();
+}

solutions/Codeforces/Codeforces Round 979 (Div. 2)/B.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+void solve() {
+   int n;
+   cin >> n;
+   string s;
+   for (int i = 0; i < n - 1; i++) s += '0';
+   s += '1';
+   cout << s << "\n";
+}
+
+int main() {
+   ios::sync_with_stdio(false);
+   cin.tie(0);
+   cout.tie(0);
+
+   int t = 1;
+   cin >> t;
+   while (t--) solve();
+}

solutions/Codeforces/Codeforces Round 979 (Div. 2)/C.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+void solve() {
+   int n;
+   cin >> n;
+   string s;
+   cin >> s;
+   bool yes = s[0] == '1' || s[n - 1] == '1';
+   for (int i = 1; !yes && i < n; i++)
+      if (s[i] == s[i - 1] && s[i] == '1') yes = true;
+   cout << (yes ? "YES" : "NO") << "\n";
+}
+
+int main() {
+   ios::sync_with_stdio(false);
+   cin.tie(0);
+   cout.tie(0);
+
+   int t = 1;
+   cin >> t;
+   while (t--) solve();
+}

solutions/Codeforces/Codeforces Round 979 (Div. 2)/D.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+vector<pair<int, int>> merge(vector<pair<int, int>> must) {
+   vector<pair<int, int>> ans;
+   sort(must.begin(), must.end());
+   if (must.empty()) return ans;
+   int curl = must[0].first, curr = must[1].second;
+   for (auto [l, r] : must) {
+      if (l > curr + 1)
+         ans.push_back({curl, curr}), curl = l, curr = r;
+      else
+         curr = max(curr, r);
+   }
+   ans.push_back({curl, curr});
+   return ans;
+}
+
+void solve() {
+   int n, q;
+   cin >> n >> q;
+   vector<int> a(n);
+   for (auto &i : a) cin >> i;
+   string s;
+   cin >> s;
+
+   vector<pair<int, int>> must;
+   for (int i = 0; i < n; i++)
+      if (a[i] != i + 1)
+         must.push_back({min(a[i] - 1, i), max(a[i] - 1, i) - 1});
+   must = merge(must);
+
+   auto needindex = [&](int idx) {
+      auto it = lower_bound(must.begin(), must.end(), make_pair(idx, idx));
+      if (it == must.end() || it->first > idx) {
+         if (it == must.begin()) return false;
+         it--;
+         if (it->second < idx)
+            return false;
+         else
+            return true;
+      } else {
+         return true;
+      }
+   };
+
+   set<int> toremove;
+   for (int i = 0; i < n - 1; i++) {
+      if (s[i] == 'L' && s[i + 1] == 'R' && needindex(i)) toremove.insert(i);
+   }
+
+   for (int i = 0; i < q; i++) {
+      int idx;
+      cin >> idx;
+      idx--;
+      s[idx] = s[idx] == 'L' ? 'R' : 'L';
+
+      if (idx + 1 < n)
+         if (s[idx] == 'L' && s[idx + 1] == 'R' && needindex(idx))
+            toremove.insert(idx);
+         else
+            toremove.erase(idx);
+
+      if (idx - 1 >= 0)
+         if (s[idx - 1] == 'L' && s[idx] == 'R' && needindex(idx - 1))
+            toremove.insert(idx - 1);
+         else
+            toremove.erase(idx - 1);
+
+      cout << (toremove.empty() ? "YES" : "NO") << "\n";
+   }
+}
+
+int main() {
+   ios::sync_with_stdio(false);
+   cin.tie(0);
+   cout.tie(0);
+
+   int t = 1;
+   cin >> t;
+   while (t--) solve();
+}