Submission #1289405

#	Time	Username	Problem	Language	Result	Execution time	Memory
1289405		muhammad-ahmad	Tracks in the Snow (BOI13_tracks)	C++20	0 / 100	2105 ms	354292 KiB

tracks

// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
#include <numeric>
#include <stack>
#include <chrono>
using namespace std;

#define int long long
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define fi first
#define se second

const int N = 4005;
int n, m, dist[N][N];
bool vis[N][N];
string s[N];
vector<int> dx = {0, 0, 1, -1}, dy = {1, -1, 0, 0};

bool check(int x, int y){
	return (x > 0 && x <= n && y > 0 && y <= m && !vis[x][y]);
}

signed bfs(){
	priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<pair<int, pair<int, int>>>> q;
	q.push({0, {1, 1}});
	vis[1][1] = 1;
	int ma = 0;
	while (q.size()){
		auto [D, coord] = q.top(); q.pop();
		auto [x, y] = coord;
		
		ma = max(ma, D);
		
		for (auto ddx : dx){
			for (auto ddy : dy){
				int cx = x + ddx, cy = y + ddy;
				if (check(cx, cy) && s[cx][cy] == s[x][y]){
					dist[cx][cy] = D;
					q.push({dist[cx][cy], {cx, cy}});
					vis[cx][cy] = 1;
				}
				else if (check(cx, cy)){
					dist[cx][cy] = D + 1;
					q.push({dist[cx][cy], {cx, cy}});
					vis[cx][cy] = 1;
				}
			}
		}
		
	}
	
	return ma;
}

void solve() {
	cin >> n >> m;
	for (int i = 1; i <= n; i++){
		cin >> s[i];
		s[i] = "." + s[i];
	}
	
	for (int i = 1; i <= n; i++){
		for (int j = 1; j <= m; j++) dist[i][j] = 1e18;
	}
	
	dist[1][1] = 0;
	cout << bfs() << endl;
	return;
}

signed main() {
    srand(chrono::steady_clock::now().time_since_epoch().count());
    int tc = 1;
    // cin >> tc;
    while (tc--) solve();
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 70