Submission #940532

#	Time	Username	Problem	Language	Result	Execution time	Memory
940532		Reverberate	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	558 ms	247844 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define MAXN 4002

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

int n, m, depth[MAXN][MAXN], ans = 1;
char snow[MAXN][MAXN];

bool inside(int x, int y) {
	return (x > -1 && x < n && y > -1 && y < m && snow[x][y] != '.');
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>n>>m;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			cin>>snow[i][j];
		}
	}
	memset(depth,0,sizeof(depth));
	deque<pair<int,int>>dq;
	dq.push_back({0,0});
	depth[0][0]=1;
	while(!dq.empty()){
		auto curr = dq.front();
		int r = curr.first, c = curr.second;
		dq.pop_front();
		ans = max(ans,depth[r][c]);
		for(int i=0;i<4;i++){
			int nr = r+dx[i], nc = c+dy[i];
			if(inside(nr,nc)&&depth[nr][nc]==0){
				if(snow[r][c]==snow[nr][nc]){
					depth[nr][nc] = depth[r][c];
					dq.push_front({nr,nc});
				}
				else{
					depth[nr][nc] = depth[r][c]+1;
					dq.push_back({nr,nc});
				}
			}
		}
	}
	cout<<ans;
}

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