Submission #897573

#	Time	Username	Problem	Language	Result	Execution time	Memory
897573		ivaziva	Mecho (IOI09_mecho)	C++14	17 / 100	48 ms	22812 KiB

mecho

#include <bits/stdc++.h>
    
using namespace std;
    
#define MAXN 810
    
long long n;
long long s;
char matrica[MAXN][MAXN];
long long dist1[MAXN][MAXN];///bee bfs
long long dist2[MAXN][MAXN];///mecho bfs
pair<long long,long long> parent[MAXN][MAXN];
queue<pair<long long,long long>> bfsq1;
queue<pair<long long,long long>> bfsq2;
    
bool check(long long x,long long y)
{
    if (x>=1 and x<=n and y>=1 and y<=n and matrica[x][y]!='T') return true;
    else return false;
}
    
void bfs1()
{
    while (bfsq1.empty()==false)
    {
        long long x=bfsq1.front().first;
        long long y=bfsq1.front().second;
        bfsq1.pop();
        if (check(x+1,y) and dist1[x+1][y]==LLONG_MAX)
        {
            dist1[x+1][y]=dist1[x][y]+1;
            bfsq1.push({x+1,y});
        }
        if (check(x-1,y) and dist1[x-1][y]==LLONG_MAX)
        {
            dist1[x-1][y]=dist1[x][y]+1;
            bfsq1.push({x-1,y});
        }
        if (check(x,y+1) and dist1[x][y+1]==LLONG_MAX)
        {
            dist1[x][y+1]=dist1[x][y]+1;
            bfsq1.push({x,y+1});
        }
        if (check(x,y-1) and dist1[x][y-1]==LLONG_MAX)
        {
            dist1[x][y-1]=dist1[x][y]+1;
            bfsq1.push({x,y-1});
        }
    }
}
    
void bfs2(long long a,long long b)
{
    dist2[a][b]=0; bfsq2.push({a,b});
    while (bfsq2.empty()==false)
    {
        long long x=bfsq2.front().first;
        long long y=bfsq2.front().second;
        bfsq2.pop();
        if (check(x+1,y) and dist2[x+1][y]==LLONG_MAX)
        {
            long long d=dist2[x][y]+1;
            if (d<dist1[x+1][y]*s) dist2[x+1][y]=d;
            else dist2[x+1][y]=-1;
            if (dist2[x+1][y]!=-1) parent[x+1][y]={x,y};
            if (dist2[x+1][y]!=-1) bfsq2.push({x+1,y});
        }
        if (check(x-1,y) and dist2[x-1][y]==LLONG_MAX)
        {
            long long d=dist2[x][y]+1;
            if (d<dist1[x-1][y]*s) dist2[x-1][y]=d;
            else dist2[x-1][y]=-1;
            if (dist2[x-1][y]!=-1) parent[x-1][y]={x,y};
            if (dist2[x-1][y]!=-1) bfsq2.push({x-1,y});
        }
        if (check(x,y+1) and dist2[x][y+1]==LLONG_MAX)
        {
            long long d=dist2[x][y]+1;
            if (d<dist1[x][y+1]*s) dist2[x][y+1]=d;
            else dist2[x][y+1]=-1;
            if (dist2[x][y+1]!=-1) parent[x][y+1]={x,y};
            if (dist2[x][y+1]!=-1) bfsq2.push({x,y+1});
        }
        if (check(x,y-1) and dist2[x][y-1]==LLONG_MAX)
        {
            long long d=dist2[x][y]+1;
            if (d<dist1[x][y-1]*s) dist2[x][y-1]=d;
            else dist2[x][y-1]=-1;
            if (dist2[x][y-1]!=-1) parent[x][y-1]={x,y};
            if (dist2[x][y-1]!=-1) bfsq2.push({x,y-1});
        }
    }
}
    
int main()
{
    cin>>n>>s;
    for (long long i=1;i<=n;i++)
    {
        for (long long j=1;j<=n;j++)
        {
            dist1[i][j]=LLONG_MAX;
            dist2[i][j]=LLONG_MAX;
        }
    }
    long long a,b;
    long long c,d;
    for (long long i=1;i<=n;i++)
    {
        for (long long j=1;j<=n;j++)
        {
            cin>>matrica[i][j];
            if (matrica[i][j]=='H')
            {
                dist1[i][j]=0;
                bfsq1.push({i,j});
            }
            if (matrica[i][j]=='M') {a=i;b=j;}
            if (matrica[i][j]=='D') {c=i;d=j;}
        }
    }
    bfs1(); bfs2(a,b);
    deque<pair<long long,long long>> dek;
    pair<long long,long long> tren={c,d};
    dek.push_front(tren);
    while (parent[tren.first][tren.second].first!=0)
    {
        pair<long long,long long> par=parent[tren.first][tren.second];
        dek.push_front(par); tren=par;
    }
    long long ans=LLONG_MAX;
    while (dek.empty()==false)
    {
        long long x=dek.front().first;
        long long y=dek.front().second;
        if (x==c and y==d) break;
        long long val=dist2[x][y];
        long long z=val/s;
        long long br;
        if (z*s==val) br=dist1[x][y]-z-1;
        else br=dist1[x][y]-z;
        ans=min(ans,br);
        dek.pop_front();
    }
    cout<<ans<<endl;
}

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:136:18: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
  136 |         if (x==c and y==d) break;
      |             ~~~~~^~~~~~~~
mecho.cpp:136:9: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  136 |         if (x==c and y==d) break;
      |         ^~
mecho.cpp:122:17: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  122 |     bfs1(); bfs2(a,b);
      |             ~~~~^~~~~
mecho.cpp:122:17: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 17 / 100