Submission #1083245

#	Time	Username	Problem	Language	Result	Execution time	Memory
1083245		vrcoder045	Tracks in the Snow (BOI13_tracks)	C++14	0 / 100	9 ms	40240 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define int long long
int P = 1000000007;
int P2 = 998244353;
#define F first
#define S second
#define pb push_back
#define mp make_pair

int dx[4]{1, 0, 0, -1}, dy[4]{0, 1, -1, 0};

void solve () {
    int h, w; cin >> h >> w;
    int arr[h][w]; string s;
    for (int i=0; i<h; ++i) {
    	cin >> s;
    	for (int j=0; j<w; ++j) {
    		arr[i][j] = (s[j] == 'F') ? 2 : ((s[j] == 'R') ? 1 : 0);
    	}
    }
    vector<vector<int>> vis(h, vector<int>(w));
    deque<pair<int,int>> dq; dq.pb(mp(0,0)); vis[0][0] = 1;
    int ans = 0;
    while (!dq.empty()) {
    	pair<int,int> node = dq.front(); dq.pop_front();
    	ans = max(ans, vis[node.F][node.S]);
    	for (int i=0; i<4; ++i) {
    		int tx = node.F+dx[i], ty = node.S+dy[i];
    		if (tx<0 || ty<0 || tx>=h || ty>=w) {continue;}
    		if (vis[tx][ty] > 0) {continue;}
    		if (arr[tx][ty]>0 && arr[tx][ty] == arr[node.F][node.S]) {
    			vis[tx][ty] = vis[node.F][node.S];
    			dq.push_front(mp(tx, ty));
    		}
    		else if (arr[tx][ty]>0 && arr[tx][ty] != arr[node.F][node.S]) {
    			vis[tx][ty] = vis[node.F][node.S]+1;
    			dq.push_back(mp(tx, ty));
    		}
    	}
    }
    // for (int i=0; i<h; ++i) {for (int j=0; j<w; ++j) {cout << vis[i][j] << " ";} cout << '\n';}
    cout << ans << '\n';
}
 
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
	    freopen("input.txt", "r", stdin);
	    freopen("output.txt", "w", stdout);
	#endif
    int t = 1;
    // cin >> t;
    for (int _t=0; _t<t;++_t) {
        // cout << "Case #" << _t+1 << ": ";
        solve();
    }
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:49:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |      freopen("input.txt", "r", stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:50:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |      freopen("output.txt", "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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