Submission #468388

#	Time	Username	Problem	Language	Result	Execution time	Memory
468388		Dan4Life	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	642 ms	235956 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define int long long
int n, m, depth[4001][4001];
int X[] = {1, -1, 0, 0};
int Y[] = {0, 0, 1, -1};
string a[4001];

bool inside(int i, int j)
{
    if(i<0 or j<0 or i>=n or j>=m or a[i][j]=='.') return false;
    return true;
}

int32_t main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n >> m;
    for(int i = 0; i < n; i++) cin >> a[i];
    depth[0][0]=1;
    deque<pair<int,int>> Q;
    Q.push_back({0,0}); int ans = 0;
    while(!Q.empty())
    {
        auto s = Q.front(); Q.pop_front();
        int x = s.first, y = s.second;
        ans = max(ans, depth[x][y]);
        for(int i = 0; i < 4; i++)
        {
            int nx = x+X[i], ny = y+Y[i];
            if(inside(nx,ny) and depth[nx][ny]==0){
                if(a[x][y]==a[nx][ny]){
                    depth[nx][ny]=depth[x][y];
                    Q.push_front({nx,ny});
                }
                else{
                    depth[nx][ny]=1+depth[x][y];
                    Q.push_back({nx,ny});
                }
            }
        }
    }
    cout << ans;
}

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