Submission #42783

#	Time	Username	Problem	Language	Result	Execution time	Memory
42783		funcsr	Paint By Numbers (IOI16_paint)	C++14	100 / 100	306 ms	48284 KiB

paint

#include "paint.h"
#include <iostream>
#include <vector>
#include <string>
#include <cassert>
using namespace std;
#define rep(i, n) for (int i=0; i<(n); i++)
#define INF 1145141919

int N, K;
int C[100];
bool dpL[200010][101], dpR[200010][101];
int white[200010], black[200010];
inline int range_white(int l, int r) { return white[r]-(l>0?white[l-1]:0); }
inline int range_black(int l, int r) { return black[r]-(l>0?black[l-1]:0); }
int W[101];

string solve_puzzle(string S, vector<int> c) {
  S = '_'+S+'_';
  N = S.length();
  K = c.size();
  rep(i, K) C[i] = c[i];
  string O(S);

  rep(i, N+1) rep(j, K+1) dpL[i][j] = false, dpR[i][j] = false;
  rep(i, N) white[i] = S[i]=='_', black[i] = S[i]=='X';
  rep(i, N-1) white[i+1] += white[i], black[i+1] += black[i];

  dpL[0][0] = true;
  rep(i, N) {
    if (range_black(i, i)) continue;
    rep(k, K+1) dpL[i+1][k] |= dpL[i][k];
    rep(k, K) {
      int l = i-C[k];
      if (range_white(l, i-1) == 0) dpL[i+1][k+1] |= dpL[l][k];
    }
  }
  assert(dpL[N][K]);

  dpR[N-1][K] = true;
  for (int i=N-1; i>0; i--) {
    if (range_black(i, i)) continue;
    rep(k, K+1) dpR[i-1][k] |= dpR[i][k];
    for (int k=1; k<=K; k++) {
      int r = i+C[k-1];
      if (range_white(i+1, r) == 0) dpR[i-1][k-1] |= dpR[r][k];
    }
  }

  rep(i, K) W[i] = -INF;
  rep(i, N) {
    bool can_be_white = false, can_be_black = false;
    rep(k, K) {
      int pos = i-1, c = C[k];
      if (pos+c<N && range_white(pos+1, pos+c)==0 && dpL[pos+1][k] && dpR[pos+c][k+1]) W[k] = pos;
      can_be_black |= (i-C[k]) <= W[k];
    }
    if (S[i] != '.') continue;
    rep(k, K+1) can_be_white |= dpL[i+1][k] && dpR[i-1][k];
    //cout<<"i="<<i<<": white="<<can_be_white<<", black="<<can_be_black<<"\n";
    assert(can_be_white || can_be_black);

    if (!can_be_white) O[i] = 'X';
    else if (!can_be_black) O[i] = '_';
    else O[i] = '?';
  }
  O.erase(O.begin()), O.pop_back();
  return O;
}

• 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