Submission #101578

#	Time	Username	Problem	Language	Result	Execution time	Memory
101578		dantoh000	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	1742 ms	113192 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> ii;
int dx[] = {1,0,-1,0}, dy[] = {0,1,0,-1};
int main(){
    int h,w;
    scanf("%d%d",&h,&w);
    char grid[h][w];
    int nonempty = 0;
    for (int i = 0; i < h; i++){
        for (int j = 0; j < w; j++){
            scanf(" %c",&grid[i][j]);
            if (grid[i][j] != '.') nonempty++;
        }
    }
    int num = 0;
    int vis[h][w];
    int ans = 1;
    char a = grid[0][0];
    char b = a^'F'^'R';
    memset(vis,0,sizeof(vis));
    deque<ii> q;
    q.push_back(ii(0,0));
    vis[0][0] = 1;
    while(q.size()){
        ii cur = q.front(); q.pop_front();
        int x = cur.first, y = cur.second;
        for (int k = 0; k < 4; k++){
            int nx = x + dx[k], ny = y + dy[k];
            if (nx >= 0 && nx < h && ny >= 0 && ny < w && vis[nx][ny] == 0 && grid[nx][ny] != '.'){
                if (grid[nx][ny] == grid[x][y]){
                    vis[nx][ny] = vis[x][y];
                    q.push_front(ii(nx,ny));
                }
                else{
                    vis[nx][ny] = vis[x][y]+1;
                    q.push_back(ii(nx,ny));
                }
                ans = max(ans,vis[nx][ny]);
                //printf("%d %d %d\n",vis[nx][ny],nx,ny);
            }
        }
    }
    printf("%d",ans);


}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:16:9: warning: unused variable 'num' [-Wunused-variable]
     int num = 0;
         ^~~
tracks.cpp:20:10: warning: unused variable 'b' [-Wunused-variable]
     char b = a^'F'^'R';
          ^
tracks.cpp:7:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&h,&w);
     ~~~~~^~~~~~~~~~~~~~
tracks.cpp:12:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf(" %c",&grid[i][j]);
             ~~~~~^~~~~~~~~~~~~~~~~~~

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