Submission #552820

#	Time	Username	Problem	Language	Result	Execution time	Memory
552820		Soul234	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	614 ms	130684 KiB

tracks

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

void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << h; if(sizeof...(t)) cerr << ", ";
    DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

#define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--)
#define R0F(i,a) ROF(i,0,a)
#define each(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pb push_back
#define tcT template<class T
#define nl "\n"

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
using str = string;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;

void setIO(string NAME = "") {
    cin.tie(0)->sync_with_stdio(0);
    if(sz(NAME)) {
        freopen((NAME + ".inp").c_str(),"r",stdin);
        freopen((NAME + ".out").c_str(),"w",stdout);
    }
}

tcT> bool ckmax(T&a, const T&b) {
    return b > a ? a = b, 1 : 0;
}

const int dx[] = {0, -1, 0, 1};
const int dy[] = {-1, 0, 1, 0};
const int MX = 4e3;
int N, M, dist[MX][MX];
str S[MX];

void solve() {
    cin>>N>>M;
    F0R(i,N) cin>>S[i];
    deque<pi> dq;
    dist[0][0] = 1;
    dq.pb({0,0});
    int ans = 0;
    while(sz(dq)) {
        int x = dq.front().first, y = dq.front().second;
        dq.pop_front();
        ckmax(ans, dist[x][y]);
        F0R(i,4) {
            int nx = x + dx[i], ny = y + dy[i];
            if(min(nx,ny)>=0 && nx < N && ny<M && !dist[nx][ny] && S[nx][ny] != '.') {
                if(S[nx][ny] == S[x][y]) {
                    dq.push_front({nx,ny});
                    dist[nx][ny] = dist[x][y];
                }
                else {
                    dq.pb({nx,ny});
                    dist[nx][ny] = dist[x][y] + 1;
                }
            }
        }
    }
    cout << ans << nl;
}

int main() {
    setIO();

    int t=1;
    //cin>>t;
    while(t-->0) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'void setIO(std::string)':
tracks.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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