Submission #625187

#	Time	Username	Problem	Language	Result	Execution time	Memory
625187		Stavab	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1173 ms	636720 KiB

tracks

#include <iostream>
#include <vector>
#include <utility>
#include <queue>

using namespace std;

vector<vector<char>> field;
vector<vector<int>> turn;
int h, w, answer = 1;
queue<pair<int, int>> points;

void scan(pair<int, int> p)
{
    int i = p.first;
    int j = p.second;
    
    if(i != 0)
    {
        if(!turn[i - 1][j] && field[i - 1][j] != '.')
        {
            if(field[i - 1][j] == field[i][j])
            {
                turn[i - 1][j] = turn[i][j];
                scan({i - 1, j});
            }
            else
            {
                turn[i - 1][j] = turn[i][j] + 1;
                points.push({i - 1, j});
            }
        }
    }
    if(j != 0)
    {
        if(!turn[i][j - 1] && field[i][j - 1] != '.')
        {
            if(field[i][j - 1] == field[i][j])
            {
                turn[i][j - 1] = turn[i][j];
                scan({i, j - 1});
            }
            else
            {
                turn[i][j - 1] = turn[i][j] + 1;
                points.push({i, j - 1});
            }
        }
    }
    if(i != h - 1)
    {
        if(!turn[i + 1][j] && field[i + 1][j] != '.')
        {
            if(field[i + 1][j] == field[i][j])
            {
                turn[i + 1][j] = turn[i][j];
                scan({i + 1, j});
            }
            else
            {
                turn[i + 1][j] = turn[i][j] + 1;
                points.push({i + 1, j});
            }
        }
    }
    if(j != w - 1)
    {
        if(!turn[i][j + 1] && field[i][j + 1] != '.')
        {
            if(field[i][j + 1] == field[i][j])
            {
                turn[i][j + 1] = turn[i][j];
                scan({i, j + 1});
            }
            else
            {
                turn[i][j + 1] = turn[i][j] + 1;
                points.push({i, j + 1});
            }
        }
    }
}

int main()
{
    scanf("%d %d", &h, &w);
    
    field.assign(h, vector<char>(w));
    turn.assign(h, vector<int>(w, 0));
    
    for(int i = 0; i < h; i++)
        for(int j = 0; j < w; j++)
            scanf(" %c", &field[i][j]);
    
    
    turn[0][0] = 1;
    points.push({0, 0});
    while(!points.empty())
    {
        answer = max(answer, turn[points.front().first][points.front().second]);
        scan(points.front());
    
        points.pop();
    }
    
    printf("%d\n", answer);
    
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:86:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |     scanf("%d %d", &h, &w);
      |     ~~~~~^~~~~~~~~~~~~~~~~
tracks.cpp:93:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |             scanf(" %c", &field[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70