Submission #1000538

#	Time	Username	Problem	Language	Result	Execution time	Memory
1000538		HUYHDUVE	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	456 ms	124064 KiB

tracks

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

typedef pair<int,int> pii;
#define ff first
#define sc second
int const INF = 2e9;

vector<int> di = {1, -1, 0, 0}, dj = {0, 0, 1, -1};

int main(){
//    freopen("A.IN", "r", stdin);
//    freopen("A.OUT", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr);
    int n, m; cin >> n >> m;
    vector<string> grid(n);
    for(auto &it : grid) cin >> it;

    vector<vector<int>> min_d(n, vector<int> (m, INF));
    min_d[0][0] = 1;
    deque<pii> q;
    q.push_back({0,0});
    int ans = 0;
    while(!q.empty()){
        pii cur = q.front();
        q.pop_front();
        ans = max(ans, min_d[cur.ff][cur.sc]);

        for(int i = 0; i < 4; i++){
            int ni = cur.ff + di[i];
            int nj = cur.sc + dj[i];
            if(ni < 0 || ni >= n || nj < 0 || nj >= m) continue;
            if(min_d[ni][nj] != INF || grid[ni][nj] == '.') continue;

            if(grid[cur.ff][cur.sc] == grid[ni][nj]){
                min_d[ni][nj] = min_d[cur.ff][cur.sc];
                q.push_front({ni, nj});
            }
            else {
                min_d[ni][nj] = min_d[cur.ff][cur.sc] + 1;
                q.push_back({ni, nj});
            }
        }
    }

    cout << ans;

}

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