bitinversions

cses/additional/bitinversions/bitinversions.cpp

@@ -0,0 +1,80 @@
+// https://cses.fi/problemset/task/1188
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int n;
+set<int> starts;
+multiset<int> lengths;
+
+void update(int x)
+{
+  if (x == 0 || x == n) return;
+
+  auto found = starts.find(x);
+  if (found != starts.end()) // this start exists already, remove it
+  {
+    int left = *prev(found), right = *next(found);
+
+    lengths.erase(lengths.find(right - x));
+    lengths.erase(lengths.find(x - left));
+
+    lengths.insert(right - left);
+
+    starts.erase(found);
+  }
+  else // this start doesn't exist, add it
+  {
+    found = starts.insert(x).first;
+
+    int left = *prev(found), right = *next(found);
+
+    lengths.erase(lengths.find(right - left));
+
+    lengths.insert(x - left);
+    lengths.insert(right - x);
+  }
+}
+
+int main()
+{
+  string s;
+  cin >> s;
+
+  n = s.size();
+
+  // prevent iterator out of bounds
+  starts.insert(0);
+  starts.insert(n);
+
+  // generate components
+  int start = 0;
+  for (int i = 1; i <= n; ++i)
+    if (i == n || s[i] != s[start])
+    {
+      starts.insert(i);
+      lengths.insert(i - start);
+      start = i;
+    }
+
+  int m;
+  cin >> m;
+
+  int x;
+  for (int i = 0; i < m; ++i)
+  {
+    cin >> x;
+    --x;
+
+    update(x);
+    update(x + 1);
+
+    cout << *lengths.rbegin() << ' ';
+  }
+
+  cout << '\n';
+
+  return 0;
+}
+
+// TODO