Submission #492832

#	Time	Username	Problem	Language	Result	Execution time	Memory
492832		niloyroot	Mecho (IOI09_mecho)	C++14	70 / 100	1098 ms	6628 KiB

mecho

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<ll>;
using pl = pair<ll,ll>;
#define pb push_back
#define form(m,it) for(auto it=m.begin(); it!=m.end(); it++)
#define forp(i,a,b) for(ll i=a; i<=b; i++)
#define forn(i,a,b) for(ll i=a; i>=b; i--)
#define newl '\n'
#define ff first
#define ss second
const ll mod = 1000000007;

void solve(){
    ll n,s; cin>>n>>s;
    char c[n+1][n+1];
    vector<pl> hives;
    ll dis[n+1][n+1]; forp(i,1,n){forp(j,1,n){dis[i][j]=INT_MAX;}}
    pl start,end;
    forp(i,1,n){
        forp(j,1,n){
            cin>>c[i][j];
            if(c[i][j]=='H'){
                hives.pb({i,j});
                dis[i][j]=0;
            }
            if(c[i][j]=='T'){
                dis[i][j]=0;
            }
            if(c[i][j]=='M'){
                start.ff=i; start.ss=j;
            }
            if(c[i][j]=='D'){
                end.ff=i; end.ss=j;
            }
        }
    }
    bool vis[n+2][n+2];
    queue<pl> q;
    ll i,j;
    for(auto p:hives){
        memset(vis,0,sizeof(vis));
        forp(i,0,n+1){vis[i][0]=1; vis[i][n+1]=1; vis[0][i]=1; vis[n+1][i]=1;}
        q.push(p);
        vis[p.ff][p.ss]=1;
        while(!q.empty()){
            i=q.front().ff; j=q.front().ss;
            q.pop();
            if(!vis[i][j+1] && (c[i][j+1]!='T' && c[i][j+1]!='H' && c[i][j+1]!='D')){
                vis[i][j+1]=1;
                dis[i][j+1]=min(dis[i][j+1],dis[i][j]+1);
                q.push({i,j+1});
            }
            if(!vis[i+1][j] && (c[i+1][j]!='T' && c[i+1][j]!='H' && c[i+1][j]!='D')){
                vis[i+1][j]=1;
                dis[i+1][j]=min(dis[i+1][j],dis[i][j]+1);
                q.push({i+1,j});
            }
            if(!vis[i][j-1] && (c[i][j-1]!='T' && c[i][j-1]!='H' && c[i][j-1]!='D')){
                vis[i][j-1]=1;
                dis[i][j-1]=min(dis[i][j-1],dis[i][j]+1);
                q.push({i,j-1});
            }
            if(!vis[i-1][j] && (c[i-1][j]!='T' && c[i-1][j]!='H' && c[i-1][j]!='D')){
                vis[i-1][j]=1;
                dis[i-1][j]=min(dis[i-1][j],dis[i][j]+1);
                q.push({i-1,j});
            }
        }
    }
    ll l=0,r=dis[start.ff][start.ss]-1,mid,len;
    queue<pair<pl,ll>> qq;
    while(l<r){
        mid=(l+r+1)/2;
        memset(vis,0,sizeof(vis));
        forp(i,0,n+1){vis[i][0]=1; vis[i][n+1]=1; vis[0][i]=1; vis[n+1][i]=1;}
        qq.push({start,0});
        vis[start.ff][start.ss]=1;
        while(!qq.empty()){
            i=qq.front().ff.ff; j=qq.front().ff.ss; len=qq.front().ss;
            qq.pop();
            if(!vis[i][j+1] && dis[i][j+1]>mid + (len+1)/s){
                vis[i][j+1]=1;
                qq.push({{i,j+1},len+1});
            }
            if(!vis[i+1][j] && dis[i+1][j]>mid + (len+1)/s){
                vis[i+1][j]=1;
                qq.push({{i+1,j},len+1});
            }
            if(!vis[i][j-1] && dis[i][j-1]>mid + (len+1)/s){
                vis[i][j-1]=1;
                qq.push({{i,j-1},len+1});
            }
            if(!vis[i-1][j] && dis[i-1][j]>mid + (len+1)/s){
                vis[i-1][j]=1;
                qq.push({{i-1,j},len+1});
            }
        }
        if(vis[end.ff][end.ss]){
            l=mid;
        } else {
            r=mid-1;
        }
    }
    mid=0;
    memset(vis,0,sizeof(vis));
    forp(i,0,n+1){vis[i][0]=1; vis[i][n+1]=1; vis[0][i]=1; vis[n+1][i]=1;}
    qq.push({start,0});
    vis[start.ff][start.ss]=1;
    while(!qq.empty()){
        i=qq.front().ff.ff; j=qq.front().ff.ss; len=qq.front().ss;
        qq.pop();
        if(!vis[i][j+1] && dis[i][j+1]>mid + (len+1)/s){
            vis[i][j+1]=1;
            qq.push({{i,j+1},len+1});
        }
        if(!vis[i+1][j] && dis[i+1][j]>mid + (len+1)/s){
            vis[i+1][j]=1;
            qq.push({{i+1,j},len+1});
        }
        if(!vis[i][j-1] && dis[i][j-1]>mid + (len+1)/s){
            vis[i][j-1]=1;
            qq.push({{i,j-1},len+1});
        }
        if(!vis[i-1][j] && dis[i-1][j]>mid + (len+1)/s){
            vis[i-1][j]=1;
            qq.push({{i-1,j},len+1});
        }
    }
    if(vis[end.ff][end.ss]){
        cout<<l<<newl;
    } else {
        cout<<-1<<newl;
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t=1; //cin>>t;
    while(t--)solve();
}

• Subtask 1: 70 / 100