Submission #1284769

#	Time	Username	Problem	Language	Result	Execution time	Memory
1284769		blackscreen1	Tracks in the Snow (BOI13_tracks)	C++20	61.04 / 100	725 ms	320976 KiB

tracks

#include <bits//stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less<long long>, rb_tree_tag,
             tree_order_statistics_node_update>
    ordered_set;
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag,
             tree_order_statistics_node_update>
    ordered_multiset;
#define ll long long
#define ld long double
#define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1))
#define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1))
#define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1))
#define lloop(m, h) for (auto l = m; l != h; l += (m < h ? 1 : -1))
#define iloop_(m, h, g) for (auto i = m; i < h; i += g)
#define jloop_(m, h, g) for (auto j = m; j < h; j += g)
#define kloop_(m, h, g) for (auto k = m; k < h; k += g)
#define lloop_(m, h, g) for (auto l = m; l < h; l += g)
#define getchar_unlocked _getchar_nolock // comment before submission
#define pll pair<ll, ll>
#define plll pair<ll, pll>
#define pllll pair<pll, pll>
#define vll vector<ll>
#define qll queue<ll>
#define dll deque<ll>
#define pqll priority_queue<ll>
#define gll greater<ll>
#define INF 1000000000000000
#define MOD1 1000000007
#define MOD2 998244353
#define MOD3 1000000009
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	ll n, m;
	cin >> n >> m;
	char a[n][m];
	iloop(0, n) jloop(0, m) cin >> a[i][j];
	ll ds[n][m];
	iloop(0, n) jloop(0, m) ds[i][j] = INF;
	bool vis[n][m];
	memset(vis, 0, sizeof(vis));
	ds[0][0] = 0;
	deque<pll> dq;
	dq.push_back({0, 0});
	while (dq.size()) {
		pll nd = dq.front();
		dq.pop_front();
		if (a[nd.first][nd.second] == '.') continue;
		if (vis[nd.first][nd.second]) continue;
		vis[nd.first][nd.second] = 1;
		if (nd.first != 0 && !vis[nd.first-1][nd.second]) {
			if (a[nd.first][nd.second] == a[nd.first-1][nd.second]) {
				ds[nd.first-1][nd.second] = ds[nd.first][nd.second];
				dq.push_front({nd.first-1, nd.second});
			}
			else if (ds[nd.first-1][nd.second] == INF) {
				ds[nd.first-1][nd.second] = ds[nd.first][nd.second] + 1;
				dq.push_back({nd.first-1, nd.second});
			}
		}
		if (nd.first != n-1 && !vis[nd.first+1][nd.second]) {
			if (a[nd.first][nd.second] == a[nd.first+1][nd.second]) {
				ds[nd.first+1][nd.second] = ds[nd.first][nd.second];
				dq.push_front({nd.first+1, nd.second});
			}
			else if (ds[nd.first+1][nd.second] == INF) {
				ds[nd.first+1][nd.second] = ds[nd.first][nd.second] + 1;
				dq.push_back({nd.first+1, nd.second});
			}
		}
		if (nd.second != 0 && !vis[nd.first][nd.second-1]) {
			if (a[nd.first][nd.second] == a[nd.first][nd.second-1]) {
				ds[nd.first][nd.second-1] = ds[nd.first][nd.second];
				dq.push_front({nd.first, nd.second-1});
			}
			else if (ds[nd.first][nd.second-1] == INF) {
				ds[nd.first][nd.second-1] = ds[nd.first][nd.second] + 1;
				dq.push_back({nd.first, nd.second-1});
			}
		}
		if (nd.second != m-1 && !vis[nd.first][nd.second+1]) {
			if (a[nd.first][nd.second] == a[nd.first][nd.second+1]) {
				ds[nd.first][nd.second+1] = ds[nd.first][nd.second];
				dq.push_front({nd.first, nd.second+1});
			}
			else if (ds[nd.first][nd.second+1] == INF) {
				ds[nd.first][nd.second+1] = ds[nd.first][nd.second] + 1;
				dq.push_back({nd.first, nd.second+1});
			}
		}
	}
	ll cans = 0;
	iloop(0, n) jloop(0, n) if (a[i][j] != '.') cans = max(cans, ds[i][j]);
	cout << cans + 1;
}

• Subtask 1: 21.6667 / 30
• Subtask 2: 39.375 / 70