Cod sursa(job #2260057)

Utilizator NewGloryMihnea Andreescu NewGlory Data 14 octombrie 2018 13:06:11
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.42 kb
#include <fstream>

using namespace std;

ifstream fin("arbint.in");
ofstream fout("arbint.out");

const int N=100000+5;
int n,v[3*N];

inline void update(int nod,int st,int dr,int id,int val)
{
    if(st==dr)
    {
        v[nod]=val;
    }
    else
    {
        int mid=(st+dr)/2;
        if(id<=mid)
        {
            update(2*nod,st,mid,id,val);
        }
        else
        {
            update(2*nod+1,mid+1,dr,id,val);
        }
        v[nod]=max(v[2*nod],v[2*nod+1]);
    }
}

inline bool com(int st,int dr,int a,int b)
{
    if(b<st || dr<a)
        return 0;
    return 1;
}

inline int ask(int nod,int st,int dr,int a,int b)
{
    if(a<=st && dr<=b)
    {
        return v[nod];
    }
    else
    {
        int mid=(st+dr)/2;
        int mx=0;
        if(com(st,mid,a,b))
        {
            mx=max(mx,ask(2*nod,st,mid,a,b));
        }
        if(com(mid+1,dr,a,b))
        {
            mx=max(mx,ask(2*nod+1,mid+1,dr,a,b));
        }
        return mx;
    }
}

int main()
{
    int n,q;
    fin>>n>>q;
    for(int i=1;i<=n;i++)
    {
        int x;
        fin>>x;
        update(1,1,n,i,x);
    }
    while(q--)
    {
        int t,a,b;
        fin>>t>>a>>b;
        if(t==0)
        {
            int ans=ask(1,1,n,a,b);
            fout<<ans<<"\n";
        }
        else
        {
            update(1,1,n,a,b);
        }
    }
    return 0;
}