Submission #730922

#	Time	Username	Problem	Language	Result	Execution time	Memory
730922		sleepntsheep	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	668 ms	166628 KiB

tracks

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

#define N 5005
char a[N][N]; int n, m, z, d[N][N], dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1};
deque<pair<int, int>> q;

int main()
{
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i++) scanf("%s", a[i] + 1);
    memset(d, 63, sizeof d);
    q.emplace_back(1, 1); d[1][1] = 1;
    while (q.size())
    {
        auto [y, x] = q.front(); q.pop_front();
        z = max(z, d[y][x]);
        for (int i = 0; i < 4; i++)
        {
            int nx = x + dx[i], ny = y + dy[i];
            if (!a[ny][nx] || a[ny][nx] == '.') continue;
            if (a[ny][nx] == a[y][x] && d[ny][nx] > d[y][x])
            {
                d[ny][nx] = d[y][x];
                q.emplace_front(ny, nx);
            }
            if (a[ny][nx] != a[y][x] && d[ny][nx] > d[y][x] + 1)
            {
                d[ny][nx] = d[y][x] + 1;
                q.emplace_back(ny, nx);
            }
        }
    }

    printf("%d", z);
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:10:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
tracks.cpp:11:39: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |     for (int i = 1; i <= n; i++) scanf("%s", a[i] + 1);
      |                                  ~~~~~^~~~~~~~~~~~~~~~

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