Submission #1240192

#	Time	Username	Problem	Language	Result	Execution time	Memory
1240192		lopkus	JOIOJI (JOI14_joioji)	C++20	100 / 100	46 ms	19272 KiB

joioji

#include <bits/stdc++.h>

#define int int64_t

signed main() {
  int n;
  std::cin >> n;
  std::vector<int> a(n + 1);
  for(int i = 1; i <= n; i++) {
    char x;
    std::cin >> x;
    if(x == 'J') {
      a[i] = 0;
    }
    else if(x == 'O') {
      a[i] = 1;
    }
    else {
      a[i] = 2;
    }
  }
  std::vector<std::vector<int>> pref(n + 2, std::vector<int>(4, 0));
  for(int i = 1; i <= n; i++) {
    for(int j = 0; j < 3; j++) {
      pref[i][j] = pref[i - 1][j];
    }
    pref[i][a[i]] += 1;
  }
  std::map<std::pair<int, int>, int> was;
  int ans = 0;
  was[{0, 0}] = 1;
  for(int i = 1; i <= n; i++) {
    std::pair<int, int> now = {pref[i][0] - pref[i][1], pref[i][0] - pref[i][2]};
    if(was[now]) {
      ans = std::max(ans, i - was[now] + 1);
    }
    else {
      was[now] = i + 1;
    }
  }
  std::cout << ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 80 / 80