Submission #1274953

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274953		KluydQ	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	816 ms	162040 KiB

tracks

#include <bits/stdc++.h>

#define respagold ios_base::sync_with_stdio(0), cin.tie(0);     
#define int long long
#define ll long long
#define int2 __int128_t
#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
#define FORR( i, x, n, d ) for( int i = x; i >= n; i -= d )
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x.size())
#define pb push_back
#define pf push_front
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define pii pair <int, int>
#define ppi pair <pair <int, int>, int>
#define pip pair <int, pair <int, int>>
#define mkp make_pair
 
using namespace std;
 
const int N = 4e3 + 12;
const int inf = 2e18;
const int mod = 1e9 + 7;
const double eps = 1e-20;

int n, m, x, y, k, used[N][N]; char a[N][N];

int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, -1, 0, 1};

void solve()
{
	cin >> n >> m;
	
	FOR( i, 1, n, 1 )
	{
		FOR( j, 1, m, 1 ) cin >> a[i][j];
	}
	queue <pii> q[2];
	q[0].push({1, 1});
	int now = 0;
	
	used[1][1] = 1;
	
	while( !q[now].empty() )
	{
		x ++;
		
		while( !q[now].empty() )
		{
			pii v = q[now].front();
			q[now].pop();
			
			FOR( i, 0, 3, 1 )
			{
				pii u = {v.F + dx[i], v.S + dy[i]};
				if( u.F > n || u.S > m || min(u.F, u.S) < 1 || a[u.F][u.S] == '.' ) continue;
				
				if( !used[u.F][u.S] )
				{
					if( a[u.F][u.S] == a[v.F][v.S] ) q[now].push(u);
					else q[now ^ 1].push(u); used[u.F][u.S] = 1;
				}
			}
		}
		now ^= 1;
	}
	cout << x << '\n';
}
signed main()
{
	respagold
	
	int test = 1;
	if( !test ) cin >> test;
	while( test -- ) solve();
}

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