Submission #960012

#	Time	Username	Problem	Language	Result	Execution time	Memory
960012		LucaLucaM	Paint By Numbers (IOI16_paint)	C++17	100 / 100	220 ms	84376 KiB

paint

#include "paint.h"

#include <cstdlib>
#include <functional>
#include <iostream>
#include <cassert>

#define debug(x) #x << " = " << x << '\n'

const int NMAX = 2e5 + 2;
const int KMAX = 100 + 2;

bool pref[NMAX + 1][KMAX + 1][2];
bool suff[NMAX + 1][KMAX + 1][2];
int sumX[NMAX + 1];
int sum_[NMAX + 1];
int worksX[NMAX + 1];

bool makeX(int l, int r) {
  return sum_[r] - sum_[l - 1] == 0;
}

bool make_(int l, int r) {
  return sumX[r] - sumX[l - 1] == 0;
}

std::string solve_puzzle(std::string s, std::vector<int> c) {
  int n = (int) s.size();
  int k = (int) c.size();
  s = '$' + s;
  c.insert(c.begin(), 0);
  std::string answer(n, '.');


  for (int i = 1; i <= n; i++) {
    sumX[i] = sumX[i - 1] + (s[i] == 'X'? +1 : 0);
    sum_[i] = sum_[i - 1] + (s[i] == '_'? +1 : 0);
  }
  pref[0][0][0] = pref[0][0][1] = true;

  for (int i = 1; i <= n; i++) {
    for (int j = 0; j <= k + 1; j++) {
      pref[i][j][0] = pref[i][j][1] = false;
    }
    if (s[i] == 'X') {
      for (int j = 0; j <= k + 1; j++) {
        if (j != 0 && i - c[j] >= 0) {
          pref[i][j][1] |= (pref[i - c[j]][j - 1][0] & makeX(i - c[j] + 1, i));
        }
      }
    } else if (s[i] == '_') {
      for (int j = 0; j <= k + 1; j++) {
        pref[i][j][0] |= pref[i - 1][j][0];
        pref[i][j][0] |= pref[i - 1][j][1];
      }
    } else {
      for (int j = 0; j <= k + 1; j++) {
        pref[i][j][0] |= pref[i - 1][j][0];
        pref[i][j][0] |= pref[i - 1][j][1];
        if (j != 0 && i - c[j] >= 0) {
          pref[i][j][1] |= (pref[i - c[j]][j - 1][0] & makeX(i - c[j] + 1, i));
        }
      }
    }
  }

  suff[n + 1][k + 1][0] = suff[n + 1][k + 1][1] = true;

  for (int i = n; i > 0; i--) {
    for (int j = 0; j <= k + 1; j++) {
      suff[i][j][0] = suff[i][j][1] = false;
    }
    if (s[i] == 'X') {
      for (int j = 0; j <= k + 1; j++) {
        if (j != 0 && i + c[j] <= n + 1) {
          suff[i][j][1] |= (suff[i + c[j]][j + 1][0] & makeX(i, i + c[j] - 1));
        }
      }
    } else if (s[i] == '_') {
      for (int j = 0; j <= k + 1; j++) {
        suff[i][j][0] |= suff[i + 1][j][0];
        suff[i][j][0] |= suff[i + 1][j][1];
      }
    } else {
      for (int j = 0; j <= k + 1; j++) {
        if (j != 0 && i + c[j] <= n + 1) {
          suff[i][j][1] |= (suff[i + c[j]][j + 1][0] & makeX(i, i + c[j] - 1));
        }
      }
      for (int j = 0; j <= k + 1; j++) {
        suff[i][j][0] |= suff[i + 1][j][0];
        suff[i][j][0] |= suff[i + 1][j][1];
      }
    }
  }

  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= k; j++) {
      if (i + c[j] <= n + 1 && pref[i - 1][j - 1][0] && suff[i + c[j]][j + 1][0] && makeX(i, i + c[j] - 1)) {
        worksX[i]++;
        worksX[i + c[j]]--;
      }
    }
  }

  for (int i = 1; i <= n; i++) {
    worksX[i] += worksX[i - 1];
  }

  for (int i = 1; i <= n; i++) {
    if (s[i] != '.') {
      answer[i - 1] = s[i];
      continue;
    }

    bool works_ = false;

    /// calculez works_

    for (int j = 0; j <= k; j++) {
      if ((pref[i - 1][j][0] || pref[i - 1][j][1]) && (suff[i + 1][j + 1][0] || suff[i + 1][j + 1][1])) {
        works_ = true;
      }
    }

    if (worksX[i] && works_) {
      answer[i - 1] = '?';
    } else if (worksX[i]) {
      answer[i - 1] = 'X';
    } else {
      answer[i - 1] = '_';
    }
  }

  return answer;
}

/**


..........
2 3 4

........
2 3 4

..._._....
1 3

.X........
1 3


**/

• 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