Cod sursa(job #2725209)

Utilizator levladiatorDragutoiu Vlad-Ioan levladiator Data 18 martie 2021 15:49:27
Problema Matrice 2 Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 2.06 kb
#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pf push_front
#define ll long long
#define ull unsigned long long
#define x first
#define y second
#define pi pair<int,int>
#define pl pair<ll,ll>

using namespace std;
ifstream fin("matrice2.in");
ofstream fout("matrice2.out");

const ll N=3e2+5,INF=1e18,MOD=666013,M=1e2+5,inf=INT_MAX;

struct edge
{
    int a,b,cost;
};

int n,q;
int v[N][N],dp[N*N],par[N*N],siz[N*N];
vector<edge> edges;

int nr(int i,int j)
{
    return (i-1)*n+j;
}
bool cmp(edge a,edge b)
{
    return a.cost>b.cost;
}

int parent(int nod)
{
    while(nod!=par[nod])
    {
        nod=par[nod];
    }
    return nod;
}
void dsu(int a,int b,int cost)
{
    a=parent(a);
    b=parent(b);
    if(a!=b)
    {
        if(siz[a]==siz[b])siz[a]++;
        if(siz[a]<siz[b])
        {
            siz[b]+=siz[a];
            par[a]=b;
            dp[a]=cost;
        }
        else
        {
            siz[a]+=siz[b];
            par[b]=a;
            dp[b]=cost;
        }
    }
}
int main()
{
    fin>>n>>q;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            fin>>v[i][j];
            if(i!=1)edges.pb({nr(i-1,j),nr(i,j),min(v[i][j],v[i-1][j])});
            if(j!=1)edges.pb({nr(i,j-1),nr(i,j),min(v[i][j],v[i][j-1])});
        }
    }
    sort(edges.begin(),edges.end(),cmp);
    for(int i=1;i<=n*n;i++)
    {
        par[i]=i;
        siz[i]=1;
    }
    for(int i=0;i<edges.size();i++)
    {
        int a=edges[i].a,b=edges[i].b,cost=edges[i].cost;
        dsu(a,b,cost);
    }
    for(int i=1;i<=q;i++)
    {
        int x1,y1,x2,y2;
        fin>>x1>>y1>>x2>>y2;
        int a=nr(x1,y1),b=nr(x2,y2),ans=1e9;
        while(a!=b)
        {
            if(siz[a]<siz[b])
            {
                ans=min(ans,dp[a]);
                a=par[a];
            }
            else
            {
                ans=min(ans,dp[b]);
                b=par[b];
            }
        }
        fout<<ans<<'\n';
    }


}