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Submission #379488

# Submission time Handle Problem Language Result Execution time Memory
379488 2021-03-18T10:30:37 Z qwerty234 Monochrome Points (JOI20_monochrome) C++14
0 / 100
 1 ms 640 KB 
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define fi first
#define se second
#define int long long

using namespace std;

const int MAXN = 1e6 + 10;

int n, blue[MAXN], red[MAXN], l1_blue[MAXN], r1_blue[MAXN], l2_blue[MAXN], r2_blue[MAXN];
int l1_red[MAXN], r1_red[MAXN], l2_red[MAXN], r2_red[MAXN];
int closest_left_red[MAXN], closest_left_blue[MAXN];
ll ans[MAXN];
char a[MAXN];

void precalc() {
  for (int i = 1; i <= n; i++) {
    blue[i + n] = blue[i] + 2 * n;
    red[i + n] = red[i] + 2 * n;
  }
  int lastred = 0, lastblue = 0;
  for (int i = 1; i <= 4 * n; i++) {
    int cur = i; if (i > 2 * n) cur -= 2 * n;
    if (a[cur] == 'B') lastblue++; else lastred++;
    closest_left_red[i] = lastred;
    closest_left_blue[i] = lastblue;
  }
  for (int i = 1; i <= n; i++) {
    l1_blue[i] = closest_left_red[blue[i]] + 1;
    r1_blue[i] = closest_left_red[(blue[i] + blue[i + n]) / 2];
    l2_blue[i] = r1_blue[i] + 1;
    r2_blue[i] = closest_left_red[blue[i + n]];

    l1_red[i] = closest_left_blue[red[i]] + 1;
    int tmp = (red[i] + red[i + n]) / 2;
    if (blue[closest_left_blue[tmp]] == tmp) {
      r1_red[i] = closest_left_blue[tmp] - 1;
      l2_red[i] = closest_left_blue[tmp];
      r2_red[i] = closest_left_blue[red[i + n]];
    } else {
      r1_red[i] = closest_left_blue[(red[i] + red[i + n]) / 2];
      l2_red[i] = r1_red[i] + 1;
      r2_red[i] = closest_left_blue[red[i + n]];
    }
  }
}

void add(int l, int r, int x) {
  if (l > r)
    return;
  l = (l + 2 * n) % n;
  r = (r + 2 * n) % n;
  if (l <= r) {
    ans[l] += x;
    ans[r + 1] -= x;
  } else {
    ans[l] += x;
    ans[1] += x;
    ans[r + 1] -= x;
  }
}

main() {
 // freopen("input.txt", "r", stdin);
  cin >> n; int b = 0, r = 0;
  for (int i = 1; i <= 2 * n; i++) {
    cin >> a[i];
    if (a[i] == 'B') {
      blue[++b] = i;
    } else {
      red[++r] = i;
    }
  }
  precalc();
  for (int i = 1; i <= n; i++) {
    if (l1_blue[i] <= r1_blue[i]) {
      add(l1_blue[i] - i, r1_blue[i] - i, -blue[i]);
    }
    if (l2_blue[i] <= r2_blue[i]) {
      add(l2_blue[i] - i, r2_blue[i] - i, blue[i + n]);
    }

    if (l1_red[i] <= r1_red[i]) {
      add(i - min(n, r1_red[i]), i - l1_red[i], -red[i + n]);
      add(i - r1_red[i], i - max(n + 1, l1_red[i]), -red[i]);
    }
    if (l2_red[i] <= r2_red[i]) {
      add(i - min(n, r2_red[i]), i - l2_red[i], red[i + n]);
      add(i - r2_red[i], i - max(n + 1, l2_red[i]), red[i]);
    }
  }
  ans[0] -= n;
  ll anss = 0, cur = 0;
  for (int i = 0; i < n; i++) {
    cur += ans[i];
    anss = max(anss, cur / 2);
  }
  cout << anss;
}

Compilation message

monochrome.cpp:65:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   65 | main() {
      |      ^

Subtask #1
0.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Incorrect 1 ms 364 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #2
0.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Incorrect 1 ms 364 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #3
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Incorrect 1 ms 364 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Incorrect 1 ms 364 KB Output isn't correct
12 Halted 0 ms 0 KB -