Submission #1169363

#	Time	Username	Problem	Language	Result	Execution time	Memory
1169363		I_FloPPed21	Mecho (IOI09_mecho)	C++20	48 / 100	142 ms	14664 KiB

mecho

#include <iostream>
#include <queue>
using namespace std;
const int N=805;
int n,m;
char mat[N][N];
int dx[]= {1,0,-1,0};
int dy[]= {0,-1,0,1};
bool inmat(int i,int j)
{
    return(i>=1&&i<=n&&j>=1&&j<=n);
}
struct mecho
{
    int x,y,val,rem;
} q[N*N+2];
bool viz[N][N];
int timp[N][N];
void citeste()
{
    cin>>n>>m;
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=n; j++)
            cin>>mat[i][j];
    }
}
void do_bees()
{

    int siz=0;
    int point=1;
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=n; j++)
        {
            timp[i][j]=1e9+3;
            if(mat[i][j]=='H')
            {
                timp[i][j]=0;
                viz[i][j]=true;
                siz++;
                q[siz]= {i,j,0,0};
            }
        }
    }
    while(point<=siz)
    {
        int x=q[point].x;
              int y=q[point].y;
        point++;
        for(int i=0; i<4; i++)
        {
            int a=x+dx[i];
            int b=y+dy[i];
            if(!inmat(a,b))
                continue;
            if(mat[a][b]=='T'||mat[a][b]=='D')
                continue;
            if(viz[a][b]==false||timp[a][b]>timp[x][y])
            {
                viz[a][b]=true;
                timp[a][b]=timp[x][y]+1;
                siz++;
                q[siz]={a,b,0,0};
            }
        }
    }
}
int ans=-1;
bool check(int val)
{
    int siz=0;
    int point=1;
    for(int i=1; i<=n; i++)
    {
        for(int j=1; j<=n; j++)
        {
            viz[i][j]=false;
            if(mat[i][j]=='M')
            {
                viz[i][j]=true;
                siz++;
                q[siz]={i,j,val,m-1};
            }
        }
    }
    while(point<=siz)
    {
        int x=q[point].x;
        int y=q[point].y;
        int val=q[point].val;
        if(timp[x][y]<=val)
        {
            viz[x][y]=false;
            break;
        }
        int cate=q[point].rem;
        point++;
        if(cate==0)
        {
            val++;
            cate=m;
        }
        cate--;
        for(int i=0; i<4; i++)
        {
            int a=x+dx[i];
            int b=y+dy[i];

            if(!inmat(a,b))
                continue;
            if(mat[a][b]=='T')
                continue;
            if(timp[a][b]>val&&viz[a][b]==false)
            {
                viz[a][b]=true;
                siz++;
                q[siz]={a,b,val,cate};
            }
        }
    }

    for(int i=1; i<=n; i++)
        for(int j=1; j<=n; j++)
            if(mat[i][j]=='D')
                if(viz[i][j]==true)
                    return true;

    return false;

}
void bin_search()
{
    int st=0,dr=n*n;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        if(check(mij))
        {
            ans=mij;
            st=mij+1;
        }
        else
        {
            dr=mij-1;
        }
    }
    cout<<ans;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    citeste();
    do_bees();
    bin_search();
    return 0;
}

• Subtask 1: 48 / 100