Submission #890069

#	Time	Username	Problem	Language	Result	Execution time	Memory
890069		math_pi	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	436 ms	137824 KiB

tracks

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

int n, m;
string s[5000];
int dp[5000][5000];
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, 1, -1};
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> n >> m;
	for(int i=0; i<n; i++) {
		cin >> s[i];
	}	
	
	deque<pair<int, int>> q;
	q.push_back({0, 0});
	dp[0][0] = 1;
	int ans = 0;
	while(!q.empty()) {
		auto me = q.front();
		q.pop_front();
		ans = max(ans, dp[me.first][me.second]);
		for(int to=0; to<4; to++) {
			int i = me.first +dx[to], j = me.second + dy[to];
			if(i>=0&&i<n&&j>=0&&j<m&&s[i][j]!='.') {
				if(dp[i][j]==0) {
					if(s[i][j]!=s[me.first][me.second]) {
						dp[i][j] = dp[me.first][me.second] + 1;
						q.push_back({i, j});
					} else {
						dp[i][j] = dp[me.first][me.second];
						q.push_front({i, j});
					}
				}
			}
		}
	}
	cout << ans << '\n';
}

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