Submission #638623

#	Time	Username	Problem	Language	Result	Execution time	Memory
638623		kakayoshi	Tracks in the Snow (BOI13_tracks)	C++14	34.38 / 100	2105 ms	60240 KiB

tracks

#include <bits/stdc++.h>
using namespace std;
#define forw(i,a,b) for(ll i=a;i<=b;i++)
#define forb(i,a,b) for(ll i=a;i>=b;i--)
#define fi first
#define se second
#define pb push_back
#define pu push
#define all(a) a.begin(),a.end()
#define getbit(mask,i) ((mask>>(i))&1)
#define minimize(a,b) (a)=min((a),(b))
typedef long long int ll;
typedef pair<int,int> pii;
typedef pair<ll,ll>  pll;
const ll maxN=5000+5;
const ll mod=1e9+7;
const ll oo=1e18;
const int tx[4]={0,1,0,-1};
const int ty[4]={1,0,-1,0};
bool vis[maxN][maxN];
char a[maxN][maxN];
int n,m,ans;
void change(int x, int y)
{
    if (a[x][y]=='R') a[x][y]='F';
    else a[x][y]='R';
    return;
}
bool outmap(int x, int y)
{
    if (1<=x && x<=n)
        if (1<=y && y<=m) return 0;
    return 1;
}
int bfs()
{
    queue<pii> p;
    memset(vis,0,sizeof vis);
    p.pu({1,1});
    vis[1][1]=1;
    char c=a[1][1];
    change(1,1);
    int cnt=1;
    while (p.size())
    {
        int x=p.front().fi;
        int y=p.front().se;
        p.pop();
        forw(i,0,3)
        {
            int xx=x+tx[i];
            int yy=y+ty[i];
            if (!vis[xx][yy] && !outmap(xx,yy) && a[xx][yy]==c)
            {
                change(xx,yy);
                vis[xx][yy]=1;
                cnt++;
                p.pu({xx,yy});
            }
        }
    }
    return cnt;
}
void solve()
{
    cin>>n>>m;
    forw(i,1,n)
        forw(j,1,m) cin>>a[i][j];
    int cnt=0;
    while (1<2)
    {
        int tmp=bfs();
        if (cnt==tmp) break;
        cnt=tmp;
        ans++;
    }
    cout<<ans;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    //freopen("bruh.inp","r",stdin);
    //freopen("bruh.out","w",stdout);
    solve();
    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 4.375 / 70