Cod sursa(job #3004731)

Utilizator MihaiCostacheCostache Mihai MihaiCostache Data 16 martie 2023 16:07:20
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("arbint.in");
ofstream fout("arbint.out");
int n, m, op, a, b, v[100005], aint[400005], sol;

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 poz, int val)
{
    if(st==dr)
        aint[nod]=val;
    else
    {
        int mid=(st+dr)/2;
        if(poz<=mid)
            update(2*nod, st, mid, poz, val);
        else
            update(2*nod+1, mid+1, dr, poz, val);
        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(b>=mid+1)
            query(2*nod+1, mid+1, dr, a, b);
    }
}

int main()
{
    fin>>n>>m;
    for(int i=1; i<=n; i++)
    {
        fin>>v[i];
    }
    build(1, 1, n);
    for(int i=1; i<=m; i++)
    {
        fin>>op>>a>>b;
        if(op==1)
        {
            v[a]=b;
            update(1, 1, n, a, b);
        }
        if(op==0)
        {
            sol=0;
            query(1, 1, n, a, b);
            fout<<sol<<"\n";
        }
    }
    return 0;
}