Cod sursa(job #3207236)

Utilizator eugenioMarinescu Eugenio eugenio Data 25 februarie 2024 16:09:57
Problema Matrice 2 Scor 35
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.7 kb
#include <fstream>
#include <algorithm>
#include <queue>
#define apmax 1000001
#define nmax 301
using namespace std;
ifstream cin("matrice2.in");
ofstream cout("matrice2.out");

int a[nmax][nmax], dp[nmax][nmax];
int n, q, sol, x1, x2, y1, y2, i, j, ivecin, jvecin, nrc, nrap, mx;
int dx[4]={-1,0,1,0};
int dy[4]={0,1,0,-1};

inline bool inside(int i, int j)
{
    return (i<=n && i>=1 && j<=n && j>=1);
}

int norm(int val)
{
    return (val<=nrap);
}

bool valid(int xs, int ys, int xf, int yf, int val)
{
    nrap++;
    queue<pair<int,int>> q;
    if(a[xs][ys]<val || a[xf][yf]<val)
        return 0;
    dp[xs][ys]=nrap;
    q.push({xs,ys});
    while(!q.empty())
    {
        i=q.front().first;
        j=q.front().second;
        q.pop();
        for(int k=0; k<4; k++)
        {
            ivecin=i+dx[k];
            jvecin=j+dy[k];
            if(a[ivecin][jvecin]>=val && inside(ivecin,jvecin) && dp[ivecin][jvecin]!=nrap)
            {
                dp[ivecin][jvecin]=nrap;
                q.push({ivecin,jvecin});
            }
        }
    }
    if(dp[xs][ys]==nrap && dp[xf][yf]==nrap)
        return 1;
    return 0;
}


int cautare(int x1, int y1, int x2, int y2)
{
    int st=1, dr=mx;
    while(st<=dr)
    {
        int mid=(st+dr)/2;
        if(valid(x1,y1,x2,y2,mid))
        {
            sol=mid;
            st=mid+1;
        }
        else
            dr=mid-1;
    }
    return sol;
}


int main()
{
    cin>>n>>q;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=n; j++)
            cin>>a[i][j], mx=max(mx,a[i][j]);

    while(q--)
    {
        cin>>x1>>y1>>x2>>y2;
        cout<<cautare(x1,y1,x2,y2)<<'\n';
    }
}