제출 #998326

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
998326		AtinaR	Mecho (IOI09_mecho)	C++14	100 / 100	159 ms	5336 KiB

mecho

#include <bits/stdc++.h>
 
using namespace std;
const int MAX=810;
const int INF=(1<<30);
int di[4]={0,0,-1,1};
int dj[4]={1,-1,0,0};
int n,s;
char mat[MAX][MAX];
int timebees[MAX][MAX];
bool visbees[MAX][MAX];
bool vis[MAX][MAX];
vector<pair<int,int> > hiveinitial;
vector<pair<int,int> > homeinitial;
int mi,mj;
int homei,homej;
bool validBees(int i, int j)
{
    if(i<0 || i>=n || j<0 || j>=n || mat[i][j]=='T'||mat[i][j]=='D'|| mat[i][j]=='H'|| visbees[i][j])return false;
    return true;
}
bool validBear(int i, int j)
{
    if(i<0 || i>=n || j<0 || j>=n || mat[i][j]!='G' || vis[i][j])return false;
    return true;
}
void bfsBees()
{
    queue<pair<int,int> > q;
    for(int i=0; i<hiveinitial.size(); i++)
    {
        int x=hiveinitial[i].first;
        int y=hiveinitial[i].second;
        q.push({x,y});
        visbees[x][y]=true;
        timebees[x][y]=0;
    }
    while(!q.empty())
    {
        pair<int,int> curr=q.front();
        q.pop();
        int x=curr.first;
        int y=curr.second;
        for(int k=0; k<4; k++)
        {
            int newi=x+di[k];
            int newj=y+dj[k];
            if(validBees(newi,newj))
            {
                q.push({newi,newj});
                timebees[newi][newj]=timebees[x][y]+1;
                visbees[newi][newj]=true;
            }
        }
    }
    return;
}
bool bearreached(int mechodis, int beedis)
{
    return mechodis/s<beedis;
}
bool canReach(int secs)
{
    queue<pair<int,int> > q;
    q.push({mi,mj});
    if(timebees[mi][mj]<=secs)
    {
        return false;
    }
    memset(vis,false,sizeof(vis));
    vis[mi][mj]=true;
    queue<int> steps;
    steps.push(0);
    while(!q.empty())
    {
        pair<int,int> curr=q.front();
        int x=curr.first;
        int y=curr.second;
        int currstep=steps.front();
        steps.pop();
        q.pop();
        for(int k=0; k<4; k++)
        {
            int newi=x+di[k];
            int newj=y+dj[k];
            if(mat[newi][newj]=='D')return true;
            if(validBear(newi,newj))
            {
                if(bearreached(currstep+1,timebees[newi][newj]-secs))
                {
                    q.push({newi,newj});
                    steps.push(currstep+1);
                    vis[newi][newj]=true;
                }
            }
        }
    }
    for(int k=0; k<4; k++)
    {
        int newi=homei+di[k];
        int newj=homej+dj[k];
        if(validBear(newi,newj)&& vis[newi][newj])return true;
    }
    return false;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>s;
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {
            cin>>mat[i][j];
            if(mat[i][j]=='H')
            {
                hiveinitial.push_back({i,j});
            }
            if(mat[i][j]=='M')
            {
                mi=i;
                mj=j;
            }
            if(mat[i][j]=='D')
            {
                homei=i;
                homej=j;
            }
        }
    }
    bfsBees();
    int b=0;
    int e=n*n;
    while(b<=e)
    {
        int mid=(b+e)/2;
        if(canReach(mid))
        {
            b=mid+1;
        }
        else
        {
            e=mid-1;
        }
    }
    cout<<b-1<<endl;
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

mecho.cpp: In function 'void bfsBees()':
mecho.cpp:30:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i=0; i<hiveinitial.size(); i++)
      |                  ~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100