Cod sursa(job #3307393)

Utilizator altomMirel Fanel altom Data 20 august 2025 16:03:18
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.47 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("arbint.in");
ofstream fout("arbint.out");

int n, m, i, sol;
int aint[400005], v[100005];

void build(int nod, int st, int dr){
    if(st==dr){
        aint[nod]=v[st];
    }else{
        int mid=(st+dr)/2;
        build(2*nod, st, mid);
        build(2*nod+1, mid+1, dr);
        aint[nod]=max(aint[2*nod], aint[2*nod+1]);
    }
}

void update(int nod, int st, int dr, int p, int x){
    if(st==dr){
        aint[nod]=x;
    }else{
        int mid=(st+dr)/2;
        if(p<=mid){
            update(2*nod, st, mid, p, x);
        }else{
            update(2*nod+1, mid+1, dr, p, x);
        }
        aint[nod]=max(aint[2*nod], aint[2*nod+1]);
    }
}

void query(int nod, int st, int dr, int a, int b){
    if(a<=st && dr<=b){
        sol=max(sol, aint[nod]);
    }else{
        int mid=(st+dr)/2;
        if(a<=mid){
            query(2*nod, st, mid, a, b);
        }
        if(mid<b){
            query(2*nod+1, mid+1, dr, a, b);
        }
    }
}

int main()
{
    fin>>n>>m;
    for(i=1;i<=n;i++){
        fin>>v[i];
    }

    build(1, 1, n);

    int t, p, x, a, b;
    for(i=1;i<=m;i++){
        fin>>t;
        if(t==0){
            fin>>a>>b;
            sol=-1e9;
            query(1, 1, n, a, b);
            fout<<sol<<'\n';
        }
        if(t==1){
            fin>>p>>x;
            update(1, 1, n, p, x);
        }
    }



    return 0;
}