Submission #891691

#	Time	Username	Problem	Language	Result	Execution time	Memory
891691		ind1v	Difference (POI11_roz)	C++11	100 / 100	614 ms	16156 KiB

roz

#include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 5;

int n;
int f[N], g[N];
vector<int> idx[26];
int ans = 0;
int b[N];
int ptr;

void solve(int mn, int mx) {
  ptr = 1;
  int i = 0, j = 0;
  while (i < (int) idx[mn].size() && j < (int) idx[mx].size()) {
    if (idx[mn][i] < idx[mx][j]) {
      b[ptr] = -1;
      ptr++;
      i++;
    } else if (idx[mx][j] < idx[mn][i]) {
      b[ptr] = 1;
      ptr++;
      j++;
    }
  }
  while (i < (int) idx[mn].size()) {
    b[ptr] = -1;
    ptr++;
    i++;
  }
  while (j < (int) idx[mx].size()) {
    b[ptr] = 1;
    ptr++;
    j++;
  }
  int sum = 0;
  for (int i = 1; i < ptr; i++) {
    sum = max(b[i], b[i] + sum);
    f[i] = sum;
  }
  sum = 0;
  for (int i = ptr - 1; i >= 1; i--) {
    sum = max(b[i], b[i] + sum);
    g[i] = sum;
  }
  for (int i = 1; i < ptr; i++) {
    if (b[i] == -1) {
      ans = max(ans, f[i] + g[i] + 1);
    }
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    char d;
    cin >> d;
    idx[d - 'a'].push_back(i);
  }
  for (int i = 0; i < 26; i++) {
    for (int j = 0; j < 26; j++) {
      if (i != j) {
        solve(i, j);
      }
    }
  }
  cout << ans << '\n';
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10