Cod sursa(job #2187206)

Utilizator mihai2003LLL LLL mihai2003 Data 26 martie 2018 12:12:45
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.4 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("arbint.in");
ofstream out("arbint.out");
int aint[400010];
int V[100010];
void build(int nod ,int st,int dr)
{
    if(st==dr)
        aint[nod]=V[st];
    else
    {
        int med=(st+dr)/2;
        build(2*nod,st,med);
        build(2*nod+1,med+1,dr);
        aint[nod]=max(aint[2*nod],aint[2*nod+1]);
    }
}
void update(int nod,int st,int dr,int pozv,int new_val)
{
    if(st==dr)
        aint[nod]=new_val;
    else
    {
        int med=(st+dr)/2;
        if(pozv<=med)update(2*nod,st,med,pozv,new_val);
        if(pozv>=med+1)
            update(2*nod+1,med+1,dr,pozv,new_val);
        aint[nod]=max(aint[2*nod],aint[2*nod+1]);
    }
}
int sol=0;
void query(int nod , int st , int dr, int a,int b)
{
    if(st>=a&&dr<=b)
        sol=max(sol,aint[nod]);
    else
    {
        int med=(st+dr)/2;
        if(a<=med)
            query(2*nod,st,med,a,b);
        if(med+1<=b)
            query(2*nod+1,med+1,dr,a,b);
    }
}
int n,m,i,a,b,p,x,t;
int main()
{
    in>>n>>m;
    for(int i=1; i<=n; i++)
        in>>V[i];
    build(1,1,n);
    for(int i=1; i<=m; i++)
    {
        in>>t>>a>>b;
        if(t==0)
        {
            sol=0;
            query(1,1,n,a,b);
            out<<sol<<'\n';
        }
        else
        {
            update(1,1,n,a,b);
        }
    }
    return 0;
}