Submission #554977

#	Time	Username	Problem	Language	Result	Execution time	Memory
554977		savackexp	Mecho (IOI09_mecho)	C++14	0 / 100	1101 ms	16768 KiB

mecho

#include<bits/stdc++.h>
using namespace std;
#define in insert
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl "\n"
#define Endl "\n"
#define ENDL "\n"
#define fi first
#define se second
#define be  begin()
#define en  end()
#define pb push_back
typedef long long ll;
typedef long double ld;
const int MOD=1e9+7;
const int MAX=2e5+1;/*
ll  binpow(ll  a, ll  b) {
    ld  res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a;
        a = a * a;
        b >>= 1;
    }

    return res;
}
unsigned long long power(unsigned long long x,
                                ll y, ll p)
{
    unsigned long long res = 1; // Initialize result

    x = x % p; // Update x if it is more than or
    // equal to p

    while (y > 0)
    {

        // If y is odd, multiply x with result
        if (y & 1)
            res = (res * x) % p;

        // y must be even now
        y = y >> 1; // y = y/2
        x = (x * x) % p;
    }
    return res;
}

unsigned long long modInverse(unsigned long long n,
                                            ll p)
{
    return power(n, p - 2, p);
}
*/
ll n  , k ;
ll dx[]={0 , 0 , 1, -1};
ll dy[]={1 , -1 , 0, 0};
char grid[805][805];
ll vis[805][805];
ll levelm[805][805];
ll levelh[805][805];
vector<pair<ll,ll>>hive;
bool valid(ll x , ll y)
{
    return x>=0 && y>=0 && x<n && y<n && grid[x][y]!='H' && grid[x][y]!='T';
}
bool valid1(ll x , ll y)
{
    return x>=0 && y>=0 && x<n && y<n  && grid[x][y]!='T';
}
pair<ll,ll>m , d;
bool check(ll u)
{
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
            {
                levelm[i][j]=1e18;
            }
        }
        memset(vis , 0 ,sizeof vis );
        queue< pair<ll,ll> >q;
        q.push({m.fi,m.se});
        vis[m.fi][m.se]=1;
        levelm[m.fi][m.se]=0;
        while(!q.empty())
        {
            pair<ll,ll>p=q.front();
            q.pop();
            for(int i=0;i<4;i++)
            {
                ll nx = p.fi +  dx[i];
                ll ny = p.se +  dy[i];
                if(!valid(nx,ny))continue;
                levelm[nx][ny]=min(levelm[p.fi][p.se]+1 ,levelm[nx][ny]);
                ll qe = (levelm[nx][ny])/k;
                if(levelh[nx][ny] + u <= qe)continue;
                if(vis[nx][ny])continue;

                vis[nx][ny] = 1;
                q.push({nx , ny});

            }

        }

    if(levelm[d.fi][d.se] != 1e18)
    {
        return true;
    }
    return false;
}

void bfs(vector<pair<ll,ll>>h)
{
    queue<pair<ll,ll> >q;
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            levelh[i][j]=1e18;
        }
    }
    for(int i=0;i<h.size();i++)
    {
        levelh[h[i].fi][h[i].se]=0;
        vis[h[i].fi][h[i].se]=1;
        q.push(h[i]);
    }
    while(!q.empty())
    {
        pair<ll,ll>p=q.front();
        q.pop();
        for(int i=0;i<4;i++)
        {

            ll nx = p.fi + dx[i];
            ll ny = p.se + dy[i];
            if(!valid1(nx,ny))continue;
            levelh[nx][ny] = min(levelh[p.fi][p.se]+1 ,levelh[nx][ny]);
            if(vis[nx][ny])continue;
            vis[nx][ny] = 1;
            q.push({nx , ny});
        }

    }
}





int main()
{

        fastio

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

        cin>>n>>k;
        for(int i=0;i<n;i++)
        {
            string s;
            cin>>s;
            for(int j=0;j<s.size();j++)
            {
                grid[i][j]=s[j];
                if(s[j]=='H')hive.pb({i,j});
                else if(s[j]=='M')m={i,j};
                else if(s[j]=='D')d={i,j};
            }
        }
        bfs(hive);
        memset(vis , 0 ,sizeof vis);
        ll l=0;
        ll r=1e18;
        ll ans=-1;
        while(l<=r)
        {
            ll mid=(l+r)/2;
            if(check(mid))
            {
                ans=mid;
                l=mid+1;
            }
            else r=mid-1;
        }
        cout<<ans<<endl;






































    return 0;
    }
/*
5 6
0 4 0
0 3 1
0 1 1
0 2 1
1 2 1
3 4 0

*/

Compilation message (stderr)

mecho.cpp: In function 'void bfs(std::vector<std::pair<long long int, long long int> >)':
mecho.cpp:125:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  125 |     for(int i=0;i<h.size();i++)
      |                 ~^~~~~~~~~
mecho.cpp: In function 'int main()':
mecho.cpp:167:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  167 |             for(int j=0;j<s.size();j++)
      |                         ~^~~~~~~~~

• Subtask 1: 0 / 100