Submission #1305407

#	Time	Username	Problem	Language	Result	Execution time	Memory
1305407		nikaa123	Tracks in the Snow (BOI13_tracks)	C++20	89.06 / 100	2101 ms	103776 KiB

tracks

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

const int dx[] = {-1,0,1,0};
const int dy[] = {0,1,0,-1};
const int N = 4e3+5;
 
int h,w;
string bd[N];
int cnt;
int d[N][N];

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    cin >> h >> w;
    for (int i = 1; i <= h; i++) {
        cin >> bd[i];
        bd[i] = " " + bd[i];
        for (int j = 1; j <= w; j++) {
            d[i][j] = INT_MAX;
        }
    }
    
    priority_queue <pair< int,pair<int,int> >, vector < pair<int,pair<int,int>> >, greater< pair<int,pair<int,int>> > > q;
    q.push({1,{1,1}});
    d[1][1]=1;
    
    int cur = 0;
    while (!q.empty()) {
        auto [x,y] = q.top().second;
        int c = q.top().first;
        q.pop();
        if (d[x][y] != c) continue;
        cur++;
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (!(1 <= nx && nx <= h && 1 <= ny && ny <= w)) continue;
            if (bd[nx][ny] == '.') continue;
            if (d[nx][ny] > d[x][y]+(bd[nx][ny]!=bd[x][y])) {
                d[nx][ny] = d[x][y]+(bd[nx][ny]!=bd[x][y]);
                q.push({d[nx][ny],{nx,ny}});
            }
        }
    }
    int ans = -INT_MAX;
    for (int i = 1; i <= h; i++) {
        for (int j = 1; j <= w; j++) {
            if (bd[i][j] == '.') continue;
            ans = max(ans,d[i][j]);
        }
    }
    cout << ans << endl;
}

• Subtask 1: 30 / 30
• Subtask 2: 59.0625 / 70