Submission #493650

#	Time	Username	Problem	Language	Result	Execution time	Memory
493650		_Monkey_	Tracks in the Snow (BOI13_tracks)	C++17	100 / 100	618 ms	105440 KiB

tracks

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

#define ll long long
#define el '\n'
#define ld long double
const int maxn=4e3+1,oo=1e9;

char c[maxn][maxn];
bool ok[maxn][maxn]={0};
int n,m,ans,x,y,nx,ny;
char cnt;
struct pnt{
    int x,y;
};
int dx[]={-1,0,1,0},dy[]={0,1,0,-1};
vector<pnt> now,net;
bool check(int xx,int yy){
    if(!ok[xx][yy]) return 0;
    ok[xx][yy]=0;
    return 1;
}
int main(){
    //freopen("T.INP","r",stdin);
    //freopen("T.OUT","w",stdout);
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin >> n >> m;
    for(int i=1;i<=n;++i)
        for(int j=1;j<=m;++j){
            cin >> c[i][j];
            if(c[i][j]!='.') ok[i][j]=1;
        }
    cnt=c[1][1];
    ok[1][1]=0;
    now.push_back({1,1});
    ans=0;
    while(!now.empty()){
        net.resize(0);
        ans++;
        while(!now.empty()){
            x=now.back().x;
            y=now.back().y;
            now.pop_back();
            for(int i=0;i<4;++i){
                nx=x+dx[i];
                ny=y+dy[i];
                if(check(nx,ny)){
                    if(c[nx][ny]==cnt) now.push_back({nx,ny});
                    else net.push_back({nx,ny});
                }
            }
        }
        now=net;
        if(cnt=='F') cnt='R';
        else cnt='F';
    }
    cout << ans;
    return 0;
}

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