Submission #625138

#	Time	Username	Problem	Language	Result	Execution time	Memory
625138		Stavab	Tracks in the Snow (BOI13_tracks)	C++14	47.50 / 100	2099 ms	156960 KiB

tracks

#include <iostream>
#include <vector>

using namespace std;

vector<vector<char>> field;
int h, w, prints = 0;
vector<int> father, chainSize;

int find(int n)
{
    if(father[n] != n)
        father[n] = find(father[n]);
        
    return father[n];
}

void join(int a, int b)
{
    a = find(a);
    b = find(b);
    
    if(a == b)
        return;
    
    if(chainSize[a] < chainSize[b])
        swap(a, b);
    
    father[b] = a;
    chainSize[a] += chainSize[b];
}

int animals(char curPrint)
{
    if(chainSize[find(0)] == prints)
        return 1;
        

    int cur = find(0);
    for(int i = 0; i < h; i++)
    {
        for(int j = 0; j < w; j++)
        {
            if(field[i][j] != curPrint)
                continue;
                
            if(i != 0)
            {
                if(find((i - 1)*w + j) == cur)
                    join(i*w + j, 0);
            }
            if(j != 0)
            {
                if(find(i*w + j - 1) == cur)
                    join(i*w + j, 0);
            }
            if(i != h - 1)
            {
                if(find((i + 1)*w + j) == cur)
                    join(i*w + j, 0);
            }
            if(j != w - 1)
            {
                if(find(i*w + j + 1) == cur)
                    join(i*w + j, 0);
            }
        }
    }
    
    if(curPrint == 'R')
        return animals('F') + 1;
    return animals('R') + 1;
}

int main()
{
    scanf("%d %d", &h, &w);
    
    field.assign(h, vector<char>(w));
    father.assign(h*w, 0);
    chainSize.assign(h*w, 1);
    for(int i = 0; i < h; i++)
    {
        for(int j = 0; j < w; j++)
        {
            scanf(" %c", &field[i][j]);
            father[i*w + j] = i*w + j;
            
            if(field[i][j] == '.')
                continue;
            
            prints++;        
            
            if(i != 0)
            {
                if(field[i - 1][j] == field[i][j])
                    join(i*w + j, (i - 1)*w + j);
            }
            if(j != 0)
            {
                if(field[i][j - 1] == field[i][j])
                    join(i*w + j, i*w + j - 1);
            }
        }
    }
    
    if(field[0][0] == 'F')
        printf("%d\n", animals('R'));
    else
        printf("%d\n", animals('F'));
    
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:77:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |     scanf("%d %d", &h, &w);
      |     ~~~~~^~~~~~~~~~~~~~~~~
tracks.cpp:86:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |             scanf(" %c", &field[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 17.5 / 70