Submission #675777

#	Time	Username	Problem	Language	Result	Execution time	Memory
675777		NONTAC	Tracks in the Snow (BOI13_tracks)	C++11	0 / 100	1 ms	212 KiB

tracks

#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> ii;

int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};
int n, m;
char grid[4002][4002];
bool vis[4002][4002];

void bfs(int si, int sj, char c)
{
    queue<ii> q;
    vis[si][sj] = true;
    q.push(ii(si, sj));
    while(!q.empty()){
        int ui = q.front().first, uj = q.front().second;
        q.pop();
        for(int i = 0; i < 4; i++){
            int vi = ui + dx[i], vj = uj + dy[i];
            if(!vis[vi][vj]){
                if(grid[vi][vj] == grid[ui][uj]){
                    vis[vi][vj] = true;
                    q.push(ii(vi, vj));
                }
            }
        }
    }

}

int main()
{
    freopen("test.in","r",stdin);
    freopen("test.out","w",stdout);

    cin>>n>>m;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++) cin>>grid[i][j];
    }

    int fox = 0, rab = 0;

    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            if(grid[i][j] == 'F'){
                if(!vis[i][j]){
                    fox++;
                    bfs(i, j, 'F');
                }
            }
        }
    }

    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            if(grid[i][j] == 'R'){
                if(!vis[i][j]){
                    rab++;
                    bfs(i, j, 'R');
                }
            }
        }
    }


    cout<<min(rab, fox) + 1;
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen("test.in","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
tracks.cpp:36:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     freopen("test.out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70