Submission #393460

#	Time	Username	Problem	Language	Result	Execution time	Memory
393460		usachevd0	Paint By Numbers (IOI16_paint)	C++14	100 / 100	352 ms	164072 KiB

paint

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define all(a) (a).begin(), (a).end()
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
using ld = long double;
template<typename T1, typename T2> bool chkmin(T1& x, T2 y) {
  return y < x ? (x = y, true) : false;
}
template<typename T1, typename T2> bool chkmax(T1& x, T2 y) {
  return y > x ? (x = y, true) : false;
}
void debug_out() {
  cerr << endl;
}
template<typename T1, typename... T2> void debug_out(T1 A, T2... B) {
  cerr << ' ' << A;
  debug_out(B...);
}
template<typename T> void mdebug_out(T* a, int n) {
  for (int i = 0; i < n; ++i) cerr << a[i];
  cerr << endl;
}
template<typename T> ostream& operator << (ostream& stream, const vector<T>& v) {
  for (auto& x : v) {
    stream << x << ' ';
  }
  return stream;
}
template<typename T1, typename T2> ostream& operator << (ostream& stream, const pair<T1, T2>& p) {
  return stream << p.first << ' ' << p.second;
}

#ifdef DEBUG
  #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
  #define mdebug(a, n) cerr << #a << ": ", mdebug_out(a, n)
#else
  #define debug(...) 1337
  #define mdebug(a, n) 1337
#endif


const int MOD = 998244353;
struct fp {
  int a;

  fp(): a(0) {}
  fp(ll x) {
    a = x % MOD;
    if (a < 0) {
      a += MOD;
    }
  }
  fp(const fp& oth): a(oth.a) {}

  fp& operator += (const fp& oth) {
    if ((a += oth.a) >= MOD) {
      a -= MOD;
    }
    return *this;
  }
  fp& operator -= (const fp& oth) {
    if ((a -= oth.a) < 0) {
      a += MOD;
    }
    return *this;
  }
  fp& operator *= (const fp& oth) {
    a = a * (ll)oth.a % MOD;
    return *this;
  }

  bool operator == (const fp& oth) {
    return a == oth.a;
  }
};
fp operator + (const fp& lhs, const fp& rhs) {
  return fp(lhs) += rhs;
}
fp operator - (const fp& lhs, const fp& rhs) {
  return fp(lhs) -= rhs;
}
fp operator * (const fp& lhs, const fp& rhs) {
  return fp(lhs) *= rhs;
}
ostream& operator << (ostream& stream, const fp& f) {
  return stream << f.a;
}

const int maxN = 200005;
const int maxK = 102;
const char code[4] = "X_.";

fp pref[maxN][maxK];
fp suff[maxN][maxK];

void rec(vector<int> s, vector<int> c, fp dp[][maxK]) {
  int n = s.size();
  int K = c.size();

  vector<int> cnt[2];
  for (int x = 0; x < 2; ++x) {
    cnt[x].assign(n + 1, 0);
    for (int i = 0; i < n; ++i) {
      cnt[x][i + 1] = cnt[x][i] + (s[i] == x);
    }
  }
  auto gt = [&](int x, int l, int r) {
    return cnt[x][r + 1] - cnt[x][l];
  };

  dp[0][0] = 1;
  for (int i = 1; i <= n; ++i) {
    if (s[i - 1] != 1) {
      for (int k = 1; k <= K; ++k) {
        int len = c[k - 1];
        if (len <= i && gt(1, i - len, i - 1) == 0 && (i - len - 1 == -1 || s[i - len - 1] != 0)) {
          dp[i][k] += dp[max(i - len - 1, 0)][k - 1];
        }
      }
    }
    if (s[i - 1] != 0) {
      for (int k = 0; k <= K; ++k) {
        dp[i][k] += dp[i - 1][k];
      }
    }
    /*debug(i);
    for (int k = 0; k <= K; ++k) {
      cerr << dp[i][k].a << ' ';
    }
    cerr << endl;*/
  }
  /*debug(dp[n][K].a);
  exit(0);*/
}

string solve_puzzle(string _s, vector<int> c) {
  int n = _s.size();
  int K = c.size();
  vector<int> s(n);
  for (int i = 0; i < n; ++i) {
    s[i] = find(code, code + 3, _s[i]) - code;
  }

//  debug(s);
//  debug(c);

  rec(s, c, pref);
  reverse(all(s));
  reverse(all(c));
  rec(s, c, suff);
  reverse(all(s));
  reverse(all(c));
  fp A = pref[n][K];

  string ans(n, '?');
  for (int i = 0; i < n; ++i) {
    if (s[i] != 2) {
      ans[i] = code[s[i]];
    } else {
      fp white = 0;
      for (int l = 0; l <= K; ++l) {
        int r = K - l;
        white += pref[i][l] * suff[n - i - 1][r];
      }
//      debug(i, white.a, A.a);
      if (white == A) {
        ans[i] = code[1];
      } else if (white == 0) {
        ans[i] = code[0];
      } else {
        ans[i] = '?';
      }
    }
  }
  return ans;
}

#ifdef DEBUG
int32_t main() {
#ifdef DEBUG
  freopen("in", "r", stdin);
#endif
  ios::sync_with_stdio(0);
  cin.tie(0);

  string s;
  cin >> s;
  int k;
  cin >> k;
  vector<int> c(k);
  for (auto& x : c) cin >> x;
  cout << solve_puzzle(s, c) << '\n';

  return 0;
}
#endif

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 21 / 21
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10