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Submission #782401

# Submission time Handle Problem Language Result Execution time Memory
782401 2023-07-13T23:14:57 Z tvladm2009 Monochrome Points (JOI20_monochrome) C++17
0 / 100
 1 ms 340 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const int N = (int) 2e5 + 7;
int n;
int aib[2 * N];
vector<int> v[2];
string s;

void update(int x) {
  x++;
  for (int i = x; i < 2 * N; i += i & -i) {
    aib[i]++;
  }
}

int query(int x) {
  x++;
  int ret = 0;
  for (int i = x; i >= 1; i -= i & -i) {
    ret += aib[i];
  }
  return ret;
}

int get(int l, int r) {
  return query(r) - query(l);
}

ll solve(int offset) {
  for (int i = 1; i <= 2 * n; i++) {
    aib[i] = 0;
  }
  vector<pair<int, int>> seg;
  for (int i = 0; i < n; i++) {
    int j = (i + offset) % n;
    seg.push_back({v[0][i], v[1][j]});
    if (seg.back().first > seg.back().second) {
      swap(seg.back().first, seg.back().second);
    }
  }
  sort(seg.begin(), seg.end());
  ll ret = 0;
  for (auto &it : seg) {
    ret += get(it.first, it.second);
    update(it.second);
  }
  return ret;
}

int main() {
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

  ///freopen("input", "r", stdin);

  cin >> n >> s;
  for (int i = 0; i < 2 * n; i++) {
    v[(s[i] == 'B')].push_back(i);
  }

  int low = 0, high = n - 1, sol = 0;
  while (low <= high) {
    int mid = (low + high) / 2;
    if (solve(mid - 1) < solve(mid)) {
      sol = mid;
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }
  cout << solve(low) << "\n";
  return 0;
}

Compilation message

monochrome.cpp: In function 'int main()':
monochrome.cpp:63:30: warning: variable 'sol' set but not used [-Wunused-but-set-variable]
   63 |   int low = 0, high = n - 1, sol = 0;
      |                              ^~~

Subtask #1
0.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -