제출 #862294

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
862294		Truly_	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	488 ms	122492 KiB

tracks

#define nametask "tracks"
#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define SZ(a) (int) a.size()
#define FOR(i, a, b) for (int i = a; i <= b; i++)
#define FOD(i, b, a) for (int i = b; i >= a; i--)

using namespace std;
typedef long long ll;
typedef pair <int, int> pi;
const pi dir[] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
const int N = 4005;

int n, m;
char a[N][N];
int d[N][N];

bool ok(int i, int j){
    return (i >= 1 && i <= n && j >= 1 && j <= m);
}

signed main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    if (fopen(nametask".inp", "r")){
        freopen(nametask".inp", "r", stdin);
        freopen(nametask".out", "w", stdout);
    }
    cin >> n >> m;
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= m; j++){
            cin >> a[i][j];
        }
    }
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= m; j++) d[i][j] = 0;
    }
    int ans = 1;
    deque <pi> dq;
    d[1][1] = 1;
    dq.push_back(mp(1, 1));
    while (!dq.empty()){
        pi top = dq.front();
        ans = max(ans, d[top.fi][top.se]);
        dq.pop_front();
        for (int i = 0; i < 4; i++){
            int u = top.fi + dir[i].fi, v = top.se + dir[i].se;
            if (ok(u, v) && (a[u][v] != '.') && (d[u][v] == 0)){
                if (a[u][v] == a[top.fi][top.se]){
                    d[u][v] = d[top.fi][top.se];
                    dq.push_front(mp(u, v));
                }
                else {
                    d[u][v] = d[top.fi][top.se] + 1;
                    dq.push_back(mp(u, v));
                }
            }
        }
    }
    cout << ans;
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

tracks.cpp: In function 'int main()':
tracks.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |         freopen(nametask".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:30:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |         freopen(nametask".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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