Submission #1065917

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065917		ortsac	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	1307 ms	998688 KiB

tracks

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

#define pii pair<int, int>
#define fr first
#define se second

const int MAXT = 4e3 + 10;
char mat[MAXT][MAXT];
bool vis[MAXT][MAXT];

int n, m;
int x[] = {-1, 0, 0, 1};
int y[] = {0, -1, 1, 0};

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

vector<pii> border;

void dfs(int i, int j) {
    vis[i][j] = 1;
    for (int k = 0; k < 4; k++) {
        int a = (i + x[k]), b = (j + y[k]);
        if (!valid(a, b) || vis[a][b] || (mat[a][b] == '.')) continue;
        if (mat[i][j] != mat[a][b]) border.push_back({a, b});
        else dfs(a, b);
    }
}

int32_t main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> mat[i][j];
        }
    }
    border.push_back({1, 1});
    int ans = 0;
    while (!border.empty()) {
        ans++;
        vector<pii> nb = border;
        border.clear();
        for (auto u : nb) dfs(u.fr, u.se);
    }
    cout << ans << "\n";
}

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