more code

codeforces/984/c.cc

@@ -0,0 +1,76 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define all(x) (x).begin(), (x).end()
+#define sz(x) static_cast<int>((x).size())
+#define FOR(x) for (int i = 0; i < (x).size(); ++i)
+
+// variable iterator macro needed
+// NOTE: can prob optimize by sorting queries
+// fix matchparen highlight
+// NOTE: didn't realize queries are independent (bruh)
+
+void solve() {
+  string s;
+  cin >> s;
+
+  auto valid = [&](int i) -> bool {
+    return i >= 0 && i < sz(s) - 3 && s[i] == '1' && s[i + 1] == '1' &&
+           s[i + 2] == '0' && s[i + 3] == '0';
+  };
+
+  int count = 0;
+
+  for (int i = 0; i < sz(s); ++i) {
+    if (valid(i)) {
+      ++count;
+    }
+  }
+
+  int q;
+  cin >> q;
+
+  for (int _ = 0; _ < q; _++) {
+    int i;
+    char v;
+    cin >> i >> v;
+    --i;
+
+    if (s[i] != v) {
+      bool left = false;
+      for (int j = i - 3; j <= i; ++j) {
+        if (valid(j)) {
+          left = true;
+          break;
+        }
+      }
+
+      s[i] = v;
+
+      bool right = false;
+      for (int j = i - 3; j <= i; ++j) {
+        if (valid(j)) {
+          right = true;
+          break;
+        }
+      }
+
+      count += (right - left);
+    }
+    cout << (count > 0 ? "YES" : "NO") << '\n';
+  }
+}
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr);
+
+  int t;
+  cin >> t;
+
+  while (t--) {
+    solve();
+  }
+
+  return 0;
+}