Submission #1091820

#	Time	Username	Problem	Language	Result	Execution time	Memory
1091820		Jakub_Wozniak	Tracks in the Snow (BOI13_tracks)	C++14	86.88 / 100	2092 ms	79800 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
const int maxn = 4009;
typedef long long ll;
int N , M;
string s[maxn];
int a , b , c;
vector <pair<int,int>> R;
bool vis[maxn][maxn];
int MAXI = 0;

void pr()
{
    R.push_back({-1,0});
    R.push_back({1,0});
    R.push_back({0,1});
    R.push_back({0,-1});
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> N >> M;
    for(int i = 0 ; i <= M+1 ; i++ )s[0] += '&';
    for(int i = 0 ; i <= M+1 ; i++ )s[N+1] += '&';

    pr();
    for(int i = 1 ; i <= N  ;i++)
    {
        cin >> s[i];
        s[i] = '&'+s[i]+'&';
    }

    priority_queue <pair<int,int>> q;
    q.push({-1,1*maxn+1});
    int i , j;
    while(!q.empty())
    {
        c = -q.top().first; 
        i = q.top().second/maxn;
        j = q.top().second%maxn;
        q.pop();
        if(vis[i][j] == 1){continue;}
        vis[i][j] = 1;
        MAXI = max(MAXI , c);

        
        for(int k = 0 ; k < R.size() ; k++)
        {

            a = i+R[k].first;
            b = j+R[k].second;
            if(s[a][b] == '&' || s[a][b] == '.' || vis[a][b] == 1)continue;
            
            if(s[a][b] == s[i][j]){ q.push({-c,a*maxn+b});}
            else {q.push({-(c+1),a*maxn+b});}
        }
    }

    cout << MAXI << '\n';


    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:49:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |         for(int k = 0 ; k < R.size() ; k++)
      |                         ~~^~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 56.875 / 70