Submission #919574

#	Time	Username	Problem	Language	Result	Execution time	Memory
919574		StefanL2005	Paint By Numbers (IOI16_paint)	C++14	59 / 100	1 ms	604 KiB

paint

#include <bits/stdc++.h>
using namespace std;
ifstream in("file.in");

int get_between(int i, int j, vector<int> &Pre_Sum)
{
    if (i > j)
        swap(i, j);
    if (i == 0)
        return Pre_Sum[j];
    return Pre_Sum[j] - Pre_Sum[i - 1];
}

int check_block_P (int i, int j, int set, vector<vector<int>> &P, string &s, vector<int> &Pre_Sum)
{
    if (j - set + 1 < 0)
        return 0;
    if (get_between(j - set + 1, j, Pre_Sum) > 0)
        return 0;
    if (j - set >= 0 && s[j - set] == 'X')
        return 0;
    if (j + 1 < s.length() && s[j + 1] == 'X')
        return 0;
    if (j - set > 0 && P[i - 1][j - set - 1] == 0)
        return 0;
    if (j - set <= 0 && i != 1)
        return 0;
    return 1;
}

int check_block_S (int i, int j, int set, vector<vector<int>> &S, string &s, vector<int> &Pre_Sum)
{
    int l = s.length();
    if (j + set - 1 >= l)
        return 0;
    if (get_between(j, j + set - 1, Pre_Sum) > 0)
        return 0;
    if (j - 1 >= 0 && s[j - 1] == 'X')
        return 0;
    if (j + set <= l && s[j + set] == 'X')
        return 0;
    if (j + set < l - 1 && S[i - 1][j + set + 1] == 0)
        return 0;
    if (j + set >= l - 1 && i != 1)
        return 0;
    return 1;
}
void fill (string &ans, int j, int set)
{
    for (int i = j; i < j + set; i++)
        if (ans[i] == '_')
            ans[i] = '?';
}

bool can_end_1 (int i, int j, vector<vector<int>> &P, vector<vector<int>> &S)
{
    int k = P.size() - 1, l = P[0].size();

    bool p1 = (i == 0 && j == 0) || (i > 0 && P[j][i - 1]);
    bool p2 = (i == l - 1 && j == k) || (i < l - 1 && S[k - j][i + 1]);
    return p1 && p2;
}

bool can_end_2 (int i, int j, int add, vector<vector<int>> &P, vector<vector<int>> &S)
{
    int k = P.size() - 1, l = P[0].size();

    bool p1 = ((j == 0 && i == 1) || (j > 0 && P[i - 1][j - 1]));
    bool p2 = ((j + add == l && k == i) || (j + add < l && S[k - i][j + add]));
    return (p1 && p2);
}
string solve_puzzle (string s, vector<int> c)
{
    int k = c.size(), l = s.length();
    bool change_back = false;
    string ans;
    vector<int> Pre_Sum(l, 0);
    vector<vector<int>> P(k + 1, vector<int> (l, 0)), S = P;

    ans.assign(l, '_');
    for (int i = 0; i < l; i++)
    {
        if (s[i] == 'X')
            ans[i] = 'X';
        if (s[i] == '_')
            Pre_Sum[i]++;
        if (i > 0)
            Pre_Sum[i]+= Pre_Sum[i - 1];
    }

    for (int i = 0; i < l; i++)
    {
        P[0][i] = 1;
        if (s[i] == 'X')
            { P[0][i] = 0; break; }
    }

    for (int i = 1; i <= k; i++)
        for (int j = 0; j < l; j++)
        {
            switch(s[j])
            {
                case '_':{
                    if (j > 0)
                        P[i][j] = P[i][j - 1];
                break;
                }
                case 'X':{
                    P[i][j] = check_block_P(i, j, c[i - 1], P, s, Pre_Sum);
                break;
                }
                case '.':{
                    if (j > 0)
                        P[i][j] = P[i][j - 1];
                    P[i][j] = max(P[i][j], check_block_P(i, j, c[i - 1], P, s, Pre_Sum));
                }
            }
        }

    for (int i = l - 1; i >= 0; i--)
    {
        S[0][i] = 1;
        if (s[i] == 'X')
            { S[0][i] = 0; break; }
    }

    for (int i = 1; i <= k; i++)
        for (int j = l - 1; j >= 0; j--)
        {
            switch(s[j])
            {
                case '_':{
                    if (j + 1 < l)
                        S[i][j] = S[i][j + 1];
                break;
                }
                case 'X':{
                    S[i][j] = check_block_S(i, j, c[k - i], S, s, Pre_Sum);
                break;
                }
                case '.':{
                    if (j + 1 < l)
                        S[i][j] = S[i][j + 1];
                    S[i][j] = max(S[i][j], check_block_S(i, j, c[k - i], S, s, Pre_Sum));
                break;
                }
            }
        }

    for (int i = 0; i < l; i++)
    {
        bool ok = false;

        for (int j = 0; j <= k; j++)
            if (can_end_1(i, j, P, S))
            { ok = true; break; }
        if (!ok)
            ans[i] = 'X';
    }

    for (int i = 1; i <= k; i++)
    {
        int add = c[i - 1];
        for (int j = 0; j <= l - add; j++)
        {
            if (get_between(j, j + add - 1, Pre_Sum) > 0)
                continue;
            if (j > 0 && ans[j - 1] == 'X')
                continue;
            if (j + add < l && ans[j + add] == 'X')
                continue;
            if (!can_end_2(i, j, add, P, S))
                continue;
            fill(ans, j, add);
        }
    }
    return ans;
}

Compilation message (stderr)

paint.cpp: In function 'int check_block_P(int, int, int, std::vector<std::vector<int> >&, std::string&, std::vector<int>&)':
paint.cpp:22:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |     if (j + 1 < s.length() && s[j + 1] == 'X')
      |         ~~~~~~^~~~~~~~~~~~
paint.cpp: In function 'std::string solve_puzzle(std::string, std::vector<int>)':
paint.cpp:75:10: warning: unused variable 'change_back' [-Wunused-variable]
   75 |     bool change_back = false;
      |          ^~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 0 / 21
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10