Submission #297792

#	Time	Username	Problem	Language	Result	Execution time	Memory
297792		eriksuenderhauf	Monochrome Points (JOI20_monochrome)	C++11	35 / 100	2072 ms	2836 KiB

monochrome

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 5;
int a[2*N];

int main() {
  ios_base::sync_with_stdio(false); cin.tie(0);
  int n; cin >> n;
  string s; cin >> s;
  for (int i = 0; i < 2*n; i++)
    a[i] = s[i] == 'B';
  ll ans = 0;
  for (int i = 0; i < n; i++) {
    int ptr[2] = {i+n, i+n}, cnt[2] = {0, 0}, cntR[2] = {0, 0};
    auto get = [&](int j) {
      return j < 2*n ? j : j-2*n;
    };
    ll val = 0;
    for (int j = i; j < i+n; j++) {
      while (get(ptr[a[j]]) != i && a[get(ptr[a[j]])] == a[j])
        cntR[a[j]]++, ptr[a[j]]++;
      ptr[a[j]]++;
      val += min(cntR[a[j]], cnt[a[j]^1]) + cnt[a[j]]++;
    }
    ans = max(ans, val);
  }
  cout << ans << "\n";
}

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 10 / 10
• Subtask 4: 0 / 65