Submission #782818

#	Time	Username	Problem	Language	Result	Execution time	Memory
782818		makanhulia	The Xana coup (BOI21_xanadu)	C++17	0 / 100	52 ms	2400 KiB

xanadu

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MAXN = 1e5 + 5;

ll n, ans = 0, val[MAXN];
bool flag = true;

ll cek(ll a, ll b, ll c) {
  if (a == 1) {
    if (b == 1) {
      if (c == 1) {
        return 2;
      } else {
        return 4;
      }
    } else {
      if (c == 1) {
        return 5;
      } else {
        return 3;
      }
    }
  } else {
    if (b == 1) {
      if (c == 1) {
        return 1;
      } else {
        return 7;
      }
    } else {
      if (c == 1) {
        return 6;
      } else {
        return 0;
      }
    }
  }
}

void update(ll state) {
  bitset<3> bs = state;
  ans += bs.count();
}

int main(){
  cin >> n;

  for (int i = 0; i < n-1; ++i)
  {
    ll tmp;
    cin >> tmp >> tmp;
  }

  for (int i = 1; i <= n; ++i)
  {
    cin >> val[i];
  }

  for (int i = 1; i <= n; ++i)
  {
    if (!flag)
    {
      break ;
    }

    if (n-i+1 < 3)
    {
      if (n-i+1 == 2) {
        if (val[i] != val[i+1])
        {
          flag = false;
        }

        break ;
      } else {
        if (val[i] == 1)
        {
          flag = false;
        }

        break ;
      }
    } else {
      ll state = cek(val[i], val[i+1], val[i+2]);
      bitset<3> bs = state;
      update(state);

      for (int j = 0; j < 3; ++j)
      {
        // Sebelum
        if (j == 2 && bs[j] && i != 1)
        {
          if (val[i-1] == 0)
          {
            flag = false;
            break ;
          }
        }

        // Sesudah
        if (j == 0 && bs[j] && i != n)
        {
          val[i+1] = val[i+1] ^ 1ll;
        }
      }
    }
  }

  if (flag) {
    cout << ans << "\n";
  } else {
    cout << "impossible\n";
  }
  return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 40
• Subtask 5: 0 / 30