Submission #1231017

#	Time	Username	Problem	Language	Result	Execution time	Memory
1231017		glupan	Tracks in the Snow (BOI13_tracks)	C++20	100 / 100	399 ms	118992 KiB

tracks

#include <bits/stdc++.h>

#define ll long long

using namespace std;

const int INF = 1e9;
const int MOD = 1000000007;
const int MAX_N = 1e5 + 5;

int dx[4]{1,-1,0,0},dy[4]{0,0,1,-1};
int dist[4005][4005];
int n,m,ans;
string snow[4005];

bool inside(int x, int y) {
    if(x >= 0 and x < n and y >= 0 and y < m and snow[x][y] != '.') return true;
    return false;
}

void solve() {
    cin >> n >> m;
    for(int i=0; i<n; i++) cin >> snow[i];
    deque<pair<int,int>>q;
    q.push_back({0,0});
    dist[0][0] = 1;
    while(!q.empty()) {
        pair<int,int> cur = q.front();
        q.pop_front();
        ans = max(ans,dist[cur.first][cur.second]);
        for(int i=0; i<4; i++) {
            int x = cur.first+dx[i], y = cur.second+dy[i];
            if(inside(x,y) and dist[x][y] == 0) {
                if(snow[cur.first][cur.second] == snow[x][y]) {
                    q.push_front({x,y});
                    dist[x][y] = dist[cur.first][cur.second];
                } else {
                    q.push_back({x,y});
                    dist[x][y] = dist[cur.first][cur.second] + 1;
                }
            }
        }
    }
    cout << ans << endl;
}


int main() {
    ios_base::sync_with_stdio(false);
	cin.tie(0);
    cout.tie(0);

	//freopen("feast.in","r",stdin);
	//freopen("feast.out","w",stdout);

    int t=1;
    while(t--)
        solve();
}

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