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Submission #299149

# Submission time Handle Problem Language Result Execution time Memory
299149 2020-09-14T14:07:23 Z eriksuenderhauf Monochrome Points (JOI20_monochrome) C++17
0 / 100
 1 ms 384 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5 + 5;
int a[4*N], nxt[3*N][2];
int idx[4*N][2], vis[2*N];
vector<int> pos;

ll solve(int n, int i) {
  int ptr[2] = {i+n, i+n};
  ll val = 0;
  for (int j = i; j < i+n; ++j)
    val += min((ptr[a[j]] = nxt[ptr[a[j]]][a[j]] + 1) - n - i - 1, j - i);
  return val;
}

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] = a[i+2*n] = s[i] == 'B';
  nxt[3*n][0] = nxt[3*n][1] = 3*n;
  for (int i = 3*n-1; i >= 0; i--) {
    nxt[i][0] = nxt[i+1][0], nxt[i][1] = nxt[i+1][1];
    nxt[i][a[i]^1] = i;
  }
  idx[0][a[0]] = 1, idx[0][a[0]^1] = 0;
  for (int i = 1; i < 4*n; i++) {
    idx[i][0] = idx[i-1][0], idx[i][1] = idx[i-1][1];
    idx[i][a[i]]++;
  }
  for (int i = 0; i < n; i++) if (s[i] == s[i+n]) {
    int hi = idx[nxt[i+n][a[i]]][a[i]^1] - idx[i][a[i]];
    if (!vis[hi])
      vis[hi] = i+1;
  }
  for (int i = 0; i <= n/2; i++) if (vis[i])
    pos.push_back(vis[i] - 1);
  ll ans = solve(n, 0);
  int lo = 0, hi = pos.size() - 1;
  while (lo <= hi) {
    int mi = (lo + hi) / 2;
    ll x1 = solve(n, pos[mi]);
    ans = max(ans, x1);
    if (lo == hi)
      break;
    if (x1 <= solve(n, pos[mi+1]))
      lo = mi + 1;
    else
      hi = mi - 1;
  }
  cout << ans << "\n";
}

Subtask #1
0.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 0 ms 384 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 0 ms 384 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 0 ms 384 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Incorrect 0 ms 384 KB Output isn't correct
6 Halted 0 ms 0 KB -