제출 #938044

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
938044		TAhmed33	Tracks in the Snow (BOI13_tracks)	C++98	97.81 / 100	1553 ms	1048576 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
int dx[4] = {0, -1, 0, 1};
int dy[4] = {1, 0, -1, 0};
const int MAXN = 4025;
int comp[MAXN][MAXN];
char arr[MAXN][MAXN]; 
int n, m;
bool check (int i, int j) {
	return (i >= 0 && i < n && j >= 0 && j < m && arr[i][j] != '.');
}
void dfs (int i, int j) {
	for (int l = 0; l < 4; l++) {
		if (check(i + dx[l], j + dy[l]) && comp[i + dx[l]][j + dy[l]] == 0 && arr[i + dx[l]][j + dy[l]] == arr[i][j]) {
			comp[i + dx[l]][j + dy[l]] = comp[i][j];
			dfs(i + dx[l], j + dy[l]);
		}
	}
}
vector <int> adj[MAXN * MAXN];
bool vis[MAXN * MAXN];
queue <int> cur;
signed main () {
	ios::sync_with_stdio(0); cin.tie(0);
	memset(vis, false, sizeof(vis));
	cin >> n >> m; assert(n < MAXN); assert(m < MAXN); for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) cin >> arr[i][j];
	int c = 0;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (comp[i][j] == 0 && arr[i][j] != '.') {
				c++;
				comp[i][j] = c;
				dfs(i, j);
			}
		}
	}
	assert(c < MAXN * MAXN);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (arr[i][j] == '.') continue;
			for (int l = 0; l < 4; l++) {
				if (check(i + dx[l], j + dy[l])) {
					if (comp[i + dx[l]][j + dy[l]] != comp[i][j]) {
						adj[comp[i][j]].push_back(comp[i + dx[l]][j + dy[l]]);
						adj[comp[i + dx[l]][j + dy[l]]].push_back(comp[i][j]);
					}
				}
			}
		}
	}
 	cur.push(comp[0][0]); vis[comp[0][0]] = 1;
	int cnt = 1;
	int ans = 0;
	while (!cur.empty()) {
		auto u = cur.size(); while (u--) {
			int k = cur.front(); cur.pop(); 
			ans = cnt;
			while (!adj[k].empty()) {
				int j = adj[k].back();
				adj[k].pop_back();
				if (!vis[j]) {
					vis[j] = 1; cur.push(j);
				}
			}
		}
		cnt++;
	}
	cout << ans << '\n';
}

• Subtask 1: 30 / 30
• Subtask 2: 67.8125 / 70