Submission #1289548

#	Time	Username	Problem	Language	Result	Execution time	Memory
1289548		m.zeeshanrashid	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	861 ms	222528 KiB

tracks

#ifdef __AVX2__
#pragma GCC target "avx2"
#endif
#pragma GCC optimize "O3"
#pragma GCC optimize "unroll-loops"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds; 
using namespace std;
#define int long long
#define elif else if
#define all(l) begin(l),end(l)
#define rall(l) rbegin(l),rend(l)
#define append push_back
#define print(l) for(auto i:l) cout<<i<<' '; cout<<endl;
#define pprint(a,b) cout<<a<<' '<<b<<endl;
#define inp(l) for(auto &i:l) cin>>i;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pai make_pair
#define endl "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define vec vector

// const int mod=998244353;
const int mod1=998244353;
const int mod=1e9+7;
const int N=4e3+5;

int n,m;
bool check(int x,int y){
	return x>=0 and x<n and y>=0 and y<m;
}

void bfs(vec<string>s){
	vec<vec<int>>dis(n+1,vec<int>(m+1,1e18));
	dis[0][0]=1;
	deque<pii>d;
	d.append({0,0});
	vec<int>dx={0,0,-1,1};
	vec<int>dy={-1,1,0,0};
	int ans=1;
	while(d.size()){
		int x=d[0].fi,y=d[0].se;
		d.pop_front();
		for(int j=0;j<4;j++){
			int cx=x+dx[j],cy=y+dy[j];
			if(check(cx,cy) and s[cx][cy]!='.' and dis[cx][cy]>1e9){
				if(s[cx][cy]==s[x][y]){
					dis[cx][cy]=dis[x][y];
					d.push_front({cx,cy});
				}
				else{
					dis[cx][cy]=dis[x][y]+1;
					ans=dis[cx][cy];
					d.append({cx,cy});
				}
			}
		}
	}
	cout<<ans<<endl;
}

int iter=1,itera=1;
void solve(){
	cin>>n>>m;
	vec<string>s(n);
	inp(s);
	bfs(s);
}
signed main(){
	// freopen("","r",stdin);
	// freopen("","w",stdout);
	ios_base::sync_with_stdio(false);
	cin.tie(NULL); 
	cout.tie(NULL);
	cout<<fixed<<setprecision(20);
	// cin>>itera;
	for(iter=1;iter<=itera;iter++) solve();
}

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