Submission #437672

#	Time	Username	Problem	Language	Result	Execution time	Memory
437672		MohammadAghil	Tracks in the Snow (BOI13_tracks)	C++14	2.19 / 100	637 ms	165472 KiB

tracks

#include <bits/stdc++.h> 
using namespace std;
typedef long long ll;
#define rep(i,l,r) for(int i = (l); i < r; i++)
#define per(i,r,l) for(int i = (r); i >= l; i--)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define pb push_back
#define ff first
#define ss second 

const ll mod = 1e9 + 7, maxn = 4e3 + 5, inf = 1e9 + 5;

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

int main(){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n, m; cin >> n >> m;
    rep(i,0,n){
        string s; cin >> s;
        rep(j,0,m){
            if(s[i] == 'R') a[i][j] = 1;
            else if(s[i] == 'F') a[i][j] = 2;
        }
    }
    vector<vector<int>> dist(n, vector<int>(m, inf));
    dist[0][0] = 1;
    deque<pair<int, int>> q; q.pb({0, 0});
    while(sz(q)){
        int i = q.front().ff, j = q.front().ss; q.pop_front();
        rep(d,0,4){
            int r = dx[d] + i, c = dy[d] + j;
            if(r < 0 || r >= n || c < 0 || c >= m || !a[r][c]) continue;
            int w = a[i][j] != a[r][c];
            if(dist[r][c] > dist[i][j] + w){
                dist[r][c] = dist[i][j] + w;
                if(w){
                    q.push_back({r, c});
                }else{
                    q.push_front({r, c});
                }
            }
        }
    }
    int ans = 0;
    rep(i,0,n){
        rep(j,0,m){
            if(a[i][j]) ans = max(ans, dist[i][j]);
        }
    }
    cout << ans;
    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 2.1875 / 70